PUBLICACIONES / PUBLICATIONS (David Montes)
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PUBLICACIONES / PUBLICATIONS (David Montes) |
PUBLICACIONES INTERNACIONALES
1994, Astrophysical Journal Supplement 90, 433.
We report high resolution observations of the Ca II H and K
and Balmer Hαlines in 53 chromospherically active
binary systems
including the RS Canum Venaticorum binaries (RS CVn)
and BY Draconis (BY Dra) classes. The rotational periods of the sample
cover a range from 0.8 to 83.2 days.
H and K emission line surface fluxes have been calculated for all the stars in
the sample. In spectra where the Hε line appears
in emission, absolute surface fluxes were also determined.
The Ca II line profiles corresponding to different seasons and orbital
phases are analysed in order to determine
the contribution of each component and to study the chromospheric
activity variations.
We have measured the Hα equivalent width of the program
stars and the Hα core emission was determined by subtraction of
the equivalent width of a presumably inactive star of the same
spectral type and luminosity class. Three different types of
Hα line profiles have been found: strong emission line,
weak emission line with strong superposed absorption profile,
and filled-in absorption line profile.
1994, Astronomy & Astrophysics 285, 609.
We present measurements of the emission core width W0 and the
wavelength separation of the K1 dips, W1, of the
Ca II H and K emission
lines observed on high-dispersion
spectra of 28 chromospherically active binary systems (RS CVn and
BY Dra stars) and 18 single active stars.
We test the width-luminosity correlations (the Wilson-Bappu
effect, and (W1, MV)) in these very active stars and
analyse the influence of the activity level (IK3) and
the rotational broadening (Vsin{i}) in these correlations.
1995, Astronomy & Astrophysics 294, 165.
We study the behaviour of the excess Hαemission
in a sample of 51 chromospherically active binary systems
(RS CVn and BY Dra classes), of different activity levels.
This sample include the 27 stars analysed
by Fernández-Figueroa et al.
(1994) and the new observations of 24 systems described
by Montes et al. (1994b).
By using the spectral subtraction technique
(subtraction of a synthesized
stellar spectrum constructed from reference stars
of similar spectral type and luminosity class)
we obtain the active-chromosphere
contribution to the Hαline in these 51 systems.
We have determined the excess
Hαemission equivalent widths and converted it to surface
fluxes.
The Hα emissions arising from each
component star were obtained when it was possible to deblend both
contributions.
The comparison of the excess Hα emission, obtained
with the spectral subtraction technique,
with other Hα activity indices allows
us to conclude that this
is the preferable activity indicator for binaries.
1995, Astronomy & Astrophysics Suplement 109, 135.
ABSTRACT
We present new spectroscopic Hα observations for a sample
of 24 chromospherically active binary systems
(RS CVn and BY Dra classes), of different activity levels.
By using the spectral subtraction technique
(subtraction of a synthesized stellar spectrum constructed
from reference stars of similar spectral type and
luminosity class) we obtain the active-chromosphere
contribution to the Hα line.
The Hα emissions arising from each
individual star were obtained when it was possible to deblend the
contribution of both components.
1995, Astronomy & Astrophysics Suplement, (Dec I), 114, 287
We present new spectroscopic observations in the Ca II H & K lines
region for a sample of 28 chromospherically active binary systems
(RS CVn and BY Dra classes), with different activity levels.
By using the spectral subtraction technique
(subtraction of a synthesized stellar spectrum constructed
from reference stars of similar spectral type and
luminosity class) we obtain the active-chromosphere
contribution to the Ca II H & K lines and to Hε line when
it is present.
We have compared the emission equivalent widths obtained with this
technique
with those obtained
by reconstruction of the absorption line
profile below the emission peak(s).
1996, Astronomy & Astrophysics, (August I), 312, 221
In this work we analyze
the behaviour of the excess Ca II H & K and Hε emissions
in a sample of 73 chromospherically active binary systems
(RS CVn and BY Dra classes), of different activity levels
and luminosity classes.
This sample includes the 53 stars analyzed
by Fern\'andez-Figueroa et al.
(1994) and the observations of 28 systems described
by Montes et al. (1995c).
By using the spectral subtraction technique
(subtraction of a synthesized
stellar spectrum constructed from reference stars
of spectral type and luminosity class similar
to those of the binary star components)
we obtain the active-chromosphere
contribution to the Ca II H & K lines in these 73 systems.
We have determined the excess
Ca II H & K emission equivalent widths and converted them into
surface fluxes.
The emissions arising from each
component were obtained when it was possible to deblend both
contributions.
We have found that the components of active binaries are generally stronger
emitters than single active stars for a given effective temperature and
rotation rate.
A slight decline of the excess Ca II H & K emissions
towards longer rotation periods, P_rot,
and larger Rossby numbers, R$_{0}$, is found.
When we use R$_{0}$ instead of P$_{\rm rot}$
the scatter is reduced and a saturation at R$_{0}$ $\approx$~0.3
is observed.
A good correlation between the excess Ca II K and
Hε chromospheric emission fluxes has been found.
The correlations obtained between the excess Ca II K emission
and other activity indicators,
(C IV in the transition region, and X-rays in the corona)
indicate that the exponents of the power-law
relations increase with the formation
temperature of the spectral features.
1996, Astronomy & Astrophysics, Letter to the Editor, June (III), 310 L29
We present simultaneous Hα, NaI D1, D2,
and HeI D3 spectroscopic observations
on the RS CVn system UX Ari.
We have found a dramatic increase in the excess Hα emission
equivalent width by a factor of 2 in an interval of 1 day that indicates
the beginning of a strong flare in this system.
The presence of the HeI D3 in emission in coincidence with the
enhancement of the Hα emission confirms the detection of a flare.
The application of the spectral subtraction technique reveals that the
core of the NaI D1 and D2 lines are also filled-in by
chromospheric emission.
1997, Astronomy & Astrophysics (Feb. III) 318, 805
As part of a long term effort to understand pre-main sequence Li burning,
we have obtained high resolution spectroscopic observations of 14 late type
stars (G0-M1) in the young open cluster IC 4665. Most of the stars have Hα
filled-in and Li absorption, as expected for their young age. From the equivalent
widths of Hα emission excess (obtained using the spectral subtraction technique)
and the LiI feature, we have derived Hα emission fluxes and photospheric
Li abundances. The mean Li abundance of IC~4665 solar-type stars is log N(Li)=3.1;
the same as in other young clusters (alpha Per, Pleiades) and T Tauri stars.
Our results support the conclusions from previous works that PMS Li depletion
is very small for masses ~1 M_sun. Among the IC 4665 late-G and early K-type
stars, there is a spread in Li abundances of about one order of magnitude. The
Li-poor IC 4665 members have low Hα excess and vsini <10. Hence, the
Li-activity-rotation connection which has been clearly established in the Pleiades
also seems to hold in IC 4665. One M-type IC 4665 star that we have observed
does not show Li, implying a very efficient Li depletion as observed in alpha
Per stars of the same spectral type. The level of chromospheric activity and
Li depletion among the low mass stars of IC 4665 is similar to that in the Pleiades.
In fact, we note that the Li abundance distributions in several young clusters
(alpha Per, Pleiades, IC 2391, IC 4665) and in post T Tauri stars are strikingly
similar. This result suggests that \ha emission and Li abundance not well correlated
with age for low mass stars between 20 and 100 Myr old. We argue that a finer
age indicator, the ``LL-clock", would be the luminosity at which the transition
between efficient Li depletion and preservation takes place for fully convective
objects. The LL-clock could allow in the near future to derive the relative
ages of young open clusters, and clarify the study of PMS evolution of cool
stars.
1997, Astronomy & Astrophysics Supp. S. (June II), 123, 473
In this work we present spectroscopic observations
centered in the spectral lines most widely used as
optical indicators of chromospheric activity
(Hα,
Hβ, CaII H & K, and
and HeI D3)
in a sample of F, G, K and M chromospherically inactive stars.
The spectra have been obtained with the aim of providing a library of
high and mid-resolution spectra to be used in the application of the
spectral subtraction technique to obtain the active-chromosphere
contribution to these lines in
chromospherically active single and binary stars.
This library can also be used for spectral classification purposes.
A digital version with all the spectra is available via ftp and the
World Wide Web (WWW).
1997, Astronomy & Astrophysics Supp. S., (Oct II), 125, 263
This is the first paper of a series aimed at studying
the chromosphere of active binary systems
using the information provided for several optical spectroscopic
features.
Simultaneous Hα, NaI D1, D2,
and HeI D3 spectroscopic observations are reported here
for 18 systems.
The chromospheric contribution in these lines have been determined
using the spectral subtraction technique.
Very broad wings have been found in the subtracted Hα profile
of some of the more active stars.
These profiles are well matched using a two-components
Gaussian fit (narrow and broad) and the broad component
could be interpreted as arising from microflaring.
Prominence-like extended material have been detected in a near-eclipse
Hα observation of the system AR Lac.
The excess emission found in the NaI D1 and D2 lines
by application of the spectral subtraction technique and the
behaviour of the Hα line in the corresponding simultaneous
observations indicate that the filling-in of the core of these lines
is a chromospheric activity indicator.
For giant stars of the sample
the HeI D3 line has been detected in absorption
in the subtracted spectra.
An optical flare has been detected in UX Ari and II Peg through
the presence of the HeI D3 in emission in coincidence with the
enhancement of the Hα emission.
1998, Astronomy & Astrophysics, (Feb I), 330, 155
The star EZ Peg, long ago classified as cataclysmic variable, has been shown
to be a chromospherically active binary system of the RS CVn-type.
In this paper we have analysed, using the spectral subtraction technique,
simultaneous spectroscopic observations of the Hα, Hβ,
NaI D1, D2, HeI D3, MgI b triplet,
CaII H & K, and CaII infrared triplet lines.
We have found that the hot component is the active star of he system,
showing strong emission in the Hα, CaII H & K, Hε,
and CaII IRT λ8498 and λ8662 lines,
and a filling-in of the Hβ line.
The variations (in time and with the orbital phase) observed in the different
indicators, formed at different height in the chromosphere,
are correlated.
Very broad wings have been found in the subtracted profiles
of Hα and CaII IRT λ8498 and λ8662 lines.
These profiles are well matched using a two-components
Gaussian fit (narrow and broad) and the broad component
could be interpreted as arising from microflaring.
The higher luminosity class of the hot component,
that our spectra seem to indicate,
could explain why the hot component is the active star of the system.
1998, Astronomy & Astrophysics Supp. S. (Mar II), 128, 485
We present a library of Utrecht echelle spectrograph (UES) observations of
a sample of F, G, K and M field dwarf stars covering the spectral range from
4800 AA to 10600 AA with a resolution of 55000. These spectra include some of
the spectral lines most widely used as optical and near-infrared indicators
of chromospheric activity such as Hβ,
Mg I b triplet, NaI D1,D2,
HeI D3, Hα,
and Ca II IRT lines, as well as a large number of photospheric lines which can
also be affected by chromospheric activity. The spectra have been compiled with
the aim of providing a set of standards observed at high-resolution to be used
in the application of the spectral subtraction technique to obtain the active-chromosphere
contribution to these lines in chromospherically active single and binary stars.
This library can also be used for spectral classification purposes. A digital
version with all the spectra is available via ftp and the World Wide Web (WWW)
in both ASCII and FITS formats.
1998, Astronomy and Astrophysics, Letter to the Editor, (Dec I), 340, L5
We report the detection of a LiI λ6708 Å
line enhancement during an unusual long-duration optical flare in
the recenltly discovered,
X-ray/EUV selected, chromospherically binary 2RE~J0743+224.
The LiI equivalength width (EW) variations
follows the temporal evolution of the flare
and large changes are observed in the intensity of the line.
The maximum LiI enhancement (40% in EW) occurs just after
the maximum chromospheric emission observed in the flare.
A significant increase of the $^6$Li/$^7$Li isotopic ratio is also detected.
No siginificant variations are detected in other photospheric lines.
Neither line blends nor starspots
seem to be the primary cause
of the observed LiI line variation.
From all this we suggest that this LiI enhancement
is produced by spallation reactions during the flare.
This is the first time that such LiI enhancement associate
with a stellar flare is reported, and probably the long-duration of
this flare is a key factor for this detection.
1999, MNRAS 305 (Number 1, 1 May), 45
We present high resolution optical echelle spectra and IUE
observations during a strong flare on 1993 December 22 in the very
active, young, rapidly rotating, single K2 dwarf LQ Hya.
The initial impulsive phase of the flare, which started sometime
between 2:42 UT and 4:07 UT, was characterized by strong optical continuum
enhancement and blue-shifted emission lines with broad wings.
The optical chromospheric lines reached their maximum intensity at
$\approx$5:31 UT, by which time the blue-shift vanished and the optical
continuum enhancement had sharply decreased. Thereafter, the line
emission slowly decreased and the lines red-shift
in a gradual phase that lasted at least two more hours.
The Mg II lines behaved similarly.
Quiescent C IV flux levels were not recovered until 21 hours later,
though a data gap and a possible second flare make the interpretation
uncertain. In addition to the typically flare-enhanced emission lines
(e.g., Hα and Hβ), we
observe He I D_3 going into emission, plus excess emission
(after subtraction of the quiescent spectrum)
in other He I and several strong neutral
metal lines (e.g., Mg I b).
Flare enhancement of the far UV continuum generally agrees with a
Si I recombination model.
We estimate the total flare energy, and discuss
the broad components, asymmetries, and Doppler shifts
seen in some of the emission lines.
1999, Astrophysical Journal Supplement Series, 123, 283 (July 1999 Vol. 123 #1)
We present here a library of Penn State Fiber Optic Echelle (FOE) observations
of a sample of field stars with spectral types F to M and luminosity classes
V to I.
The spectral coverage is from 3800 AA to 10000 AA with
nominal resolution 12000.
These spectra include many of
the spectral lines most widely used as
optical and near-infrared indicators of chromospheric activity
such as the Balmer lines (Hα
to Hε),
Ca II H & K,
Mg I b triplet,
Na I D1,D2,
He I D3,
and Ca II IRT lines, as well as a large number of
photospheric lines, which can also be affected by chromospheric activity,
and temperature sensitive photospheric features such
as TiO bands.
The spectra have been compiled with the aim of providing a set of
standards observed at medium-resolution.
We have extensively used such data for the study of active chromosphere
stars by
applying a spectral subtraction technique.
However, the data set presented here can also be utilized in a wide
variety of
ways ranging from radial velocity templates to study of variable stars
and stellar population synthesis.
This library can also be used for spectral classification purposes,
and determination of atmospheric parameters (T_eff}, log{g},
[Fe/H]).
A digital version with all the fully reduced spectra
is available via ftp and the
World Wide Web (WWW) in FITS format.
2000, Astronomy & Astrophysics Supp. S., 146, 103
This is the third paper of a series aimed at studying
the chromosphere of active binary systems
using the information provided for several optical spectroscopic
features.
High resolution echelle spectra
including all the optical chromospheric activity indicators
from the Ca II H & K to Ca II IRT lines are analysed here for 16 systems.
The chromospheric contribution in these lines has been determined
using the spectral subtraction technique.
2001, Monthly Notices of the Royal Astronomical Society, MNRAS 328, 45
This is the first paper of a series aimed at studying
the properties of late-type stars members of young stellar kinematic groups.
We center our study in classical young moving groups as:
Local Association (Pleiades moving group, 20 - 150 Myr),
IC 2391 supercluster (35 Myr),
Ursa Major group (Sirius supercluster, 300 Myr),
and Hyades supercluster (600 Myr);
as well as in recently identified groups as:
Castor moving group (200 Myr).
2001, Astronomy & Astrophysics, A&A 379, 976
We present here high resolution echelle spectra taken during three
observing runs of 14 single late-type stars identified in our previous
studies (Montes et al. 2001b, hereafter Paper I) as possible members
of different young stellar kinematic groups
(Local Association (20 - 150 Myr), Ursa Major group (300 Myr),
Hyades supercluster (600 Myr), and IC 2391 supercluster (35 Myr)).
Radial velocities have been determined by cross correlation
with radial velocity standard stars and used together with precise
measurements of proper motions and parallaxes taken from
Hipparcos and Tycho-2 Catalogues, to calculate Galactic space motions
(U, V, W) and to apply Eggen's kinematic criteria.
The chromospheric activity level of these stars have been analysed
using the information provided for several optical spectroscopic
features (from the Ca II H & K to Ca II IRT lines)
that are formed at different heights in the chromosphere.
The Li I 6707.8 Å line equivalent width (EW) has been determined and
compared in the EW(Li I) versus spectral type diagram with the EW(Li I)
of stars members of well known young open clusters of different ages,
in order to obtain an age estimation.
All these data allow us to analyse in more detail the membership of these
stars in the different young stellar kinematic groups.
Using both kinematic and spectroscopic criteria we have confirmed
PW And, V368 Cep, V383 Lac, EP Eri, DX Leo, HD 77407, and EK Dra
as members of the Local Association and V834 Tau, pi^{1} UMa, and GJ 503.2
as members of the Ursa Major group.
A clear rotation-activity dependence has been found in these stars.
2002, Astronomy & Astrophysics 389, 524
We present high resolution echelle spectra taken during
four observing runs from 1999 to 2001 of the recently,
X-ray/EUV selected chromospherically active binary
BK Psc (2RE J0039+103).
Our observations confirm the single-lined spectroscopic binary (SB1) nature
of this system and allow us to obtain, for the first time,
the orbital solution of the system as in the case of a SB2 system.
We have determined precise radial velocities of both components:
for the primary by using the cross correlation technique,
and for the secondary by using its chromospheric emission lines.
We have obtained a near circular orbit with an orbital period
of 2.1663 days, very close to its photometric period of 2.24 days
(indicating synchronous rotation).
The spectral type (K5V) we determined for our spectra and the mass ratio
(1.8) and minimum masses (Msin^3i) resulting from the orbital
solution are compatible with the observed K5V primary
and an unseen M3V secondary.
Using this spectral classification, the projected rotational
velocity (vsini, of 17.1 km s-1)
obtained from the width of the cross-correlation function,
and the data provided by Hipparcos we have derived other
fundamental stellar parameters.
The kinematics and the non- detection of the Li I indicate
that it is an old star.
The analysis of the optical chromospheric activity indicators
from the Ca II H & K to Ca II IRT lines,
by using the spectral subtraction technique, indicates that
both components of the binary system show
high levels of chromospheric activity.
Ha emission above the continuum from both components is a
persistent feature of this system during
the period 1999 to 2001 of our observations as well as in previous
observations.
The Ha and Hb emission seems
to arise from prominence-like material, and the Ca II IRT emission
from plage-like regions.
2003, Astronomy & Astrophysics, A&A 397, 285
We present simultaneous and continuous
observations of the Ha, Hb,
HeI D3, NaI D1,D2 doublet and the CaII
H&K lines for the RS CVn system HR 1099. The spectroscopic
observations were obtained during the MUSICOS 1998
campaign involving several observatories and instruments,
both echelle and long-slit spectrographs. During
this campaign, HR 1099 was observed almost
continuously for more than 8 orbits of 2.8 days.
Two large optical flares were
observed, both showing an
increase in the emission of Ha,
CaII H & K, Hb and HeI D3 and a strong filling-in of the NaI
D1,D2 doublet.
Contemporary photometric observations were carried out with
the robotic telescopes APT-80 of Catania and Phoenix-25 of
Fairborn Observatories. Maps of the distribution
of the spotted regions
on the photosphere of the binary components were derived
using the Maximum Entropy and Tikhonov
photometric regularization criteria.
Rotational modulation was observed in Ha and HeI D3
in anti-correlation with the photometric light curves. Both
flares occurred at the same binary phase (0.85),
suggesting that these events
took place in the same
active region.
Simultaneous X-ray observations,
performed by ASM on board RXTE, show several
flare-like events, some of which
correlate well with the observed optical
flares. Rotational modulation in the X-ray light
curve has been detected with minimum flux when the
less active G5V star was in
front. A periodicity in the X-ray flare-like events was also found.
2003, Astronomy & Astrophysics, A&A, 411, 489
High resolution echelle spectra of PW And (HD 1405) have been taken during
eight observing runs from 1999 to 2002. The detailed analysis of the spectra
allow us to determine its spectral type (K2V), mean heliocentric radial velocity
(V_hel = -11.15 km/s) rotational velocity (vsin{i} = 22.6 km/s), and equivalent
width of the lithium line 6707.8 Å (EW(LiI) = 273 mÅ). The kinematic (Galactic
Velocity (U, V, W)) confirms its membership of the Local Association moving
group, in agreement with the age (30 to 80 Myrs) inferred from the color magnitude
diagram and the lithium equivalent width. Photospheric activity (presence of
cool spots that disturb the profiles of the photospheric lines) has been detected
as changes in the the bisectors of the cross correlation function (CCF) resulting
of cross-correlate the spectra of PW And with the spectrum of a non active star
of similar spectral type. These variations of the CCF bisectors are related
to the variations in the measured radial velocities and are modulated with a
period similar to the photometric period of the star. At the same time, chromospheric
activity has been analyzed, using the spectral subtraction technique and simultaneous
spectroscopic observations of the Hα, Hβ, NaI D_1 and D_2, HeI D_3,
MgI b triplet, CaII H&K, and CaII infrared triplet lines. A flare was observed
during the last observing run of 2001, showing an enhancement in the observed
chromospheric lines. A less powerful flare was observed on 2002 August 23. The
variations of the chromospheric activity indicators seem to be related to the
photospheric activity. A correlation between radial velocity, changes in the
CCF bisectors and equivalent width of different chromospheric lines is observed
with a different behaviour between epochs 1999, 2001 and 2002.
2006, Astrophysical Journal, ApJ, 643, 1160
The latest results in the research of forming planetary systems
have led several authors to compile a sample of candidates for searching
for planets in the vicinity of the sun. The young stellar associations
are indeed excellent laboratories for this study, but some of them
are not close enough to allow the detection of planets through
adaptive optics techniques.
However, the existence of very close young moving groups can solve this
problem.
Here we have compiled the members of the nearest young moving groups,
as well as a list of new candidates from our study of late-type stars
possible members of young stellar kinematic groups, studying their
membership using spectroscopic and photometric criteria.
2006, Astronomy & Astrophysics, A&A, 452, 987
We report the results of a high temporal resolution spectroscopic monitoring of the flare star AD Leo.
During 4 nights, more than 600 spectra were taken in the optical range using the Isaac Newton Telescope
(INT) and the Intermediate Dispersion Spectrograph (IDS). We have observed a large number of short and weak
flares occurring very frequently (flare activity > 0.71 hours-1).
This is in favour of the very important role that flares can play in stellar coronal heating.
The detected flares are non white-light flares and, though most of solar flares belong to this kind,
very few such events had been previously observed on stars. The behaviour of different chromospheric
lines (Balmer series from Hα to H_11, Ca II H & K, Na I D_1 & D_2, He I 4026 AA and He I D_3)
has been studied in detail for a total of 14 flares.
We have also estimated the physical parameters of the flaring plasma by using a procedure which assumes
a simplified slab model of flares.
All the obtained physical parameters are consistent with previously derived values for stellar flares,
and the areas - less than 2.3% of the stellar surface - are comparable with the size inferred for other
solar and stellar flares.
Finally, we have studied the relationships between the physical parameters and the area, duration,
maximum flux and energy released during the detected flares.
2006, Astrophysical Journal, ApJ, 648, 683
We report the detection of the first extrasolar planet, ET-1 (HD 102195b),
using the Exoplanet Tracker (ET), a new generation Doppler instrument. The
planet orbits HD 102195, a young star with solar metallicity that may be part
of the local association. The planet imparts radial velocity variability to the
star with a semiamplitude of 63.4 ± 2.0 m s-1 and a period of 4.11 days. The
planetary minimum mass (msin i) is 0.488 ± 0.015 MJ .
The planet was initially detected in the spring of 2005 with the Kitt Peak
National Observatory (KPNO) 0.9 m coudé feed telescope. The detection was
confirmed by radial velocity observations with the ET at the KPNO 2.1 m telescope
and also at the 9 m Hobby-Eberly Telescope (HET) with its High Resolution
Spectrograph. This planetary discovery with a 0.9 m telescope around
a V = 8.05 magnitude star was made possible by the high throughput of the
instrument: 49% measured from the fiber output to the detector. The ET’s
interferometer-based approach is an effective method for planet detection. In
addition, the ET concept is adaptable to multiple-object Doppler observations
or very high precision observations with a cross-dispersed echelle spectrograph
to separate stellar fringes over a broad wavelength band.
In addition to spectroscopic observations of HD 102195, we obtained brightness
measurements with one of the automated photometric telescopes (APTs) at
Fairborn Observatory. Those observations reveal that HD 102195 is a spotted
variable star with an amplitude of ~0.015 mag and a 12.3 ± 0.3 day period.
This is consistent with spectroscopically observed Ca II H and K emission levels
and line broadening measurements but inconsistent with rotational modulation
of surface activity as the cause of the radial velocity variability. Our photometric
observations rule out transits of the planetary companion.
2007, Astronomy & Astrophysics, A&A, 472, 587
This is the fifth paper in a series aimed at studying the chromospheres
of active binary systems using several optical spectroscopic indicators
to obtain or improve orbital solution and fundamental stellar parameters.
We present here the study of FF UMa (2RE J0933+624), a recently
discovered, X-ray/EUV selected, active binary with strong Hα
emission. The objectives of this work are, to find orbital solutions and
define stellar parameters from precise radial velocities and carry out an
extensive study of the optical indicators of chromospheric activity.
We obtained high resolution echelle spectroscopic observations during
five observing runs from 1998 to 2004. We found radial velocities by cross
correlation with radial velocity standard stars to achieve the best
orbital solution. We also measured rotational velocity by
cross-correlation techniques and have studied the kinematic by galactic
space-velocity components (U, V, W) and Eggen criteria. Finally, we
have determined the chromospheric contribution in optical spectroscopic
indicators, from Ca II H & K to Ca II IRT lines, using the
spectral subtraction technique.
We have found that this system presents an orbital period variation,
higher than previously detected in other RS CVn systems. We determined an
improved orbital solution, finding a circular orbit with a period of 3.274
days. We derived the stellar parameters, confirming the subgiant nature of
the primary component (M_P = 1.67 M_Sun and Rsini_P = 2.17 R_Sun)
and obtained rotational velocities (vsini), of 33.57+-0.45 km/s
and 32.38+-0.75 km/s for the primary and secondary components respectively.
From our kinematic study, we can deduce its membership to the Castor moving group.
Finally, the activity study has given us a better understanding of the possible mechanism that
produce the orbital period variation.
2008, Astronomy & Astrophysics, A&A, 491, 515
Aims. We study in detail nine sources in the direction of the young σ Orionis cluster, which is considered to be a unique site for
studying stellar and substellar formation. The nine sources were selected because of their peculiar properties, such as extremely-red
infrared colours or excessively strong Hα emission for their blue optical colours.
2009, Astronomical Journal, AJ, 137, 3965
This paper describes a multiwavelengh optical study of chromospheres in two X-ray/EUV
selected active binary stars with strong Hα emission, V789 Mon (2RE J0725-002) and GZ Leo
(2RE J1101+223). The goal of the study is to determine radial velocities and fundamental
stellar parameters in chromospherically active binary systems in order to include them in the
activity-rotation and activity-age relations. We carried out high resolution echelle spectroscopic
observations and applied spectral subtraction technique in order to measure emission excesses due
to chromosphere. The detailed study of activity indicators allowed us to characterize the presence
of different chromospheric features in these systems and enabled to include them in a larger
activity-rotation survey. We computed radial velocities of the systems using cross correlation with
the radial velocity standards. The double-line spectral binarity was confirmed and the orbital
solutions improved for both systems. In addition, other stellar parameters such as: spectral types,
projected rotational velocities (vsini), and the equivalent width of the lithium LiI λ6707.8 Å
absorption line were determined.
2009, Astronomy & Astrophysics, A&A, 499, 129
Context. The associations and moving groups of young stars are excellent laboratories to investigate the stellar formation in the solar
neighborhood. Previous results confirmed that a non-negligible fraction of old main-sequence stars is present in the lists of possible members of
the young stellar kinematic groups. A detailed study on the properties of these samples is needed to separate the young stars from old
main-sequence stars with similar space motion, in order to identify the origin of these structures.
2010, Astronomy & Astrophysics, A&A, 520, A79
Context. Chromospheric activity produces both photometric and spectroscopic variations that can be mistaken as planets. Large spots
crossing the stellar disc can produce planet-like periodic variations in the light curve of a star. Moreover, spots clearly affect the
spectral line profiles. Such perturbations will in turn affect the line centroids creating a radial velocity jitter that might “contaminate”
the variations induced by a planet. Precise chromospheric activity measurements are needed to estimate the activity-induced noise
that should be expected for a given star.
2010, Astronomy & Astrophysics, A&A, 514, A97
Aims.
We present a compilation of spectroscopic data from a survey of
144 chromospherically active young stars in the solar neighborhood
which may be used to investigate different aspects of the formation
and evolution of the solar neighborhood in terms of kinematics and
stellar formation history. The data have already been used by us in several
studies. With this paper, we make all these
data accessible to the scientific community for future studies on different
topics.
1992, Anales de Física 88, 39.
We report here high and medium resolution
Balmer Hα line
profiles for 11 chromospherically active binary systems
including the class of RS Canum Venaticorum binaries (RS CVn)
and BY Draconis (BY Dra) with a total range of rotation periods
from 0.8 to 24 days. We have obtained different types of
Hα line
profiles: strong emission line, weak emission line with strong
superposed absorption profile and filled-in absorption line
profile. We have measured the Hα
equivalent width of the program
stars and the Hα core emission was determined by subtraction of
the equivalent width of a presumably inactive star with the same
spectral type and luminosity class.
High resolution observations of Hα and Ca II H and K have been
carried out at Calar Alto and Roque de Los Muchachos
Observatories. The H and K observations at two different phases
of MM Her has allowed us to derived that the two components are
chromospherically active being the activity level of the cool
component much higher.
On the contrary AR Psc shows H and K emission from only one
component at all the orbital phases, this star presents also an
important Hε emission.
The Hα observations confirm the different chromospheric
behaviour above mentioned.
We report high resolution observations of
Hαand the Ca~II H and K
lines in five chromospherically active
binaries, which present the Hαline in emission above the
continuum.
Hαequivalent widths (EW) have been determined and Ca~II H and K
surface fluxes have been calculated.
1994, I Reunión Científica de la Sociedad Española de
Astronomía.
Se presentan observaciones espectroscópicas de resolución intermedia
en la región de la línea Hβ de cinco sistemas binarios con
actividad cromosférica (AR Psc, UX Ari, V833 Tau, KZ And, II Peg).
A sample of 83 chromospherically active
binary systems including the RS Canum Venaticorum binaries (RS CVn)
and BY Draconis (BY Dra) classes has been studied
by using the spectral subtraction technique
(subtraction of a synthesized stellar spectrum constructed
from reference stars of spectral type and luminosity class similar
to those of the binary star components).
With this technique
we have obtain the active-chromosphere
contribution to the Hα line in 51 systems, and to the Ca II
H & K lines in 73 systems and 19 single active stars.
1995, Stellar Surface Structure, IAU Symp 176, Poster Proceedings,
Strassmeier K. (ed), p. 167
Enhanced emission cores in the Ca II resonance lines
H and K, are the primary optical indicators of chromospheric
activity. However, the Balmer Hα and Hβ lines can also be used
as
chromospheric activity indicators, especially in the chromospherically
active
binary systems (RS CVn and BY Dra) characterized by high levels of
activity.
1998, in ASP Conf. Ser. 154,
Cool Stars, Stellar Systems, and the Sun,
10th Cambridge Workshop ,
eds. R.A. Donahue & J.A. Bookbinder (San Francisco: ASP), CD-1516
In our analysis of the Hα line,
using the spectral subtraction technique,
in chromospherically active binary systems and in
weak-lined T Tauri stars (WTTS), we have found
that in some stars the subtracted Hα
emission line profile has very broad wings,
and is not well matched using a single-Gaussian fit.
These profiles have therefore been fitted using
two Gaussian components: a narrow component having a FWHM of
45-90 km/s and a broad component with a FWHM ranging from
133 to 470 km/s.
This broad component
could be interpreted as arising from microflaring
that occurs in
the chromosphere by similarity with the
broad components also found by other authors
in the chromospheric MgII h & k lines
and in several transition region lines of active stars.
The microflares are frequent, short-duration, energetically
weak disturbances, i.e. they are the low-energy extension of flares,
and therefore have large-scale motions associated that could
explain the broad wings observed in these lines.
A correlation between the contribution of the broad components
and the degree of stellar activity seems to be
present.
In some cases the line is asymmetric and the
fit is better matched when the broad component is blue-shifted
or red-shifted with respect to the narrow component.
These asymmetries are also observed during the impulsive and gradual phases
of solar and stellar flares, and favour the interpretation of the broad
component as due to upward and downward motions produced by microflaring
in the chromosphere.
The chromospheric activity of weak-lined T Tauri stars: simultaneous
Hα and Ca II H & K observations
1998, in ASP Conf. Ser. 154,
The Tenth Cambridge Workshop on Cool Stars, Stellar Systems, and the
Sun , eds. R.A. Donahue & J.A. Bookbinder (San Francisco: ASP),
CD-1772
Simultaneous Halpha and Ca ii H & K spectroscopic observations are reported here for 20 weak line T Tauri stars (WTTS) with photometric rotational periods well determined. In the WTTS, contrary to the classical T Tauri stars (CTTS), the emission lines are not influenced by the presence of circumstellar disks and accretion processes and the chromospheric contribution to these lines may be determined by means of the spectral subtraction technique. By using these chromospheric excess emissions we will study the flux-flux and rotation-activity relationships in order to get insights into the mechanisms which drive solar-like stellar activity in this kind of low mass pre-main sequence stars. We discuss here in more detail preliminary results for three WTTS: V773 Tau and V410 Tau which present short term chromospheric variability , and LkCa7 which shows strong emission in the Halpha, higher Balmer lines (Hdelta, Hepsilon, Hzeta, Heta and Htheta) and Ca ii H & K lines. Very broad wings have been found in the subtracted Halpha profile of V773 Tau and V410 Tau, which could be interpreted as arising from microflaring.
2000, in ASP Conf. Ser. 198, 203:
Stellar clusters and associations: convection, rotation, and dynamos
2000, in ASP Conf. Ser. 198, 475:
Stellar clusters and associations: convection, rotation, and dynamos
Ca II H & K and Hαemissions
in chromospherically active binary systems (RS CVn and BY Dra)
Fernández-Figueroa M.J., Montes D., De Castro E., Cornide M.,
ABSTRACT
Citations
"Lithium Abundance and Stellar Activity in a sample of
RS CVn and BY Dra Stars",
1993, A&A 274, 373.
"The Age-Mass Relation for Chromospherically Active Binaries. I.
The Evolutionary Status",
1994, A&A 290, 137.
"A CaII and MgII Luminosity-Emission width data base",
1994, A&AS 108, 611
"Spot activity of RS CVn system ζ And as observed
in HeI λ10830 Å and CaII lines",
1995, IAU Symp 176, p.181
"Hαspectra of selected ROSAT
active-chromosphere stars from Mt. John University Observatory",
1995, IAU Symp 176, p.175
"Long-term monitoring of active stars. IV. UBV(RI)_c_
observations obtained at La Silla in December 1989",
1995, A&AS 111, 507
"A critical analysis of the Wilson-Bappu relationship",
1995, 9th Cool stars
"An Automated search for variability in chromospherically active
stars",
1995, AJ 110, 2926
"Are the rotational axes perpendicular to the orbital planes in
the binary systems II. Main Sequence and Short-period RS CVn stars",
1995, Acta Astron. 45, 725
"Chromospherically active stars. XV. HD 8357=AR Psc, and
extremely active RS CVn system" ,
1996, AJ 112, 269
"Environments of active close binaries I. ER Vulpeculae" ,
1997, A&A 318, 60
A new H alpha. survey of chromospherically active binaries (II) ,
1997, Ap&SS 246, 39
"Hαemission in the
chromospherically active binari sigma2 Coronae Borealis (TZ CrB)",
1997, A&A 320, 101
"Time-series photometric spot modeling. III. Thirty years in
the life of HK Lacertae",
1997 A&A 321, 811
"The Age-Mass Relation for Chromospherically Active Binaries. II.
Lithium depletion in dwarfs components",
1997, A&A 326, 780.
"Chromospherically active stars. XVI. The double-lined binary
42 Cam ",
1997, AJ 114, 2747
"Chromospherically active stars. XVII. The double-lined binary 54 Cam
= AE Lyn",
1998, AJ 115, 1153
"BD +05 deg706: A New Member of the Class
of ``Cool Algols''",
1998, AJ 115, 2028
"A period study of the RS CVn-type binary ER Vulpeculae",
1998, Ap&SS 257, 1
"The fundamental parameters, chromospheric activity and magnetic field measurements of HR 5553",
1998, ApASS 257, 259
"Optical spectroscopy of X-ray sources in the old open cluster M 67",
1999, A&A 347, 866
"Catalogue and bibliography of the UV Cet-type flare stars and related objects
in the solar vicinity",
1999, A&AS 139, 555
"AR Lacertae: Halpha chromospheric emission and radial velocities
from long-term optical spectroscopy",
2000, A&A 358, 1007
"Radio, X-ray, and EUV Coronal Variability of the
Short-Period RS CVn Binary sigma^2 Coronae Borealis",
2000, ApJ, 554, 953
"Extreme Ultraviolet Explorer Observations of lambda Andromedae",
2001, ApJ, 554, 1079
"New Physical Elements of HR 7428 and its Hα Behaviour",
2001, A&A 375, 100
"An optical study of X-ray sources in the old open clusters NGC 752 and NGC 694",
2001, A&A 375, 387
"Long-term starspot evolution, activity cycle and orbital
period variation of SZ Pisciumi",
2001, A&A 376, 1011
"Spectroscopic and photometric observations of the
short-period RS CVn star RT And",
2001, A&A 378, 102
"Spectroscopic and photometric observations of the
short-period RS CVn-type star SV Cam",
2002, A&A 386, 548
"Hα Spectroscopy and BV Photometry of RT Lacertae",
2002, A&A, 388, 298
"Spectroscopic and photometric observations of the short-period RS CVn-type star CG Cyg",
2003, A&A, 400, 623
"Absolute Properties of the Eclipsing Binary Star RT Coronae Borealis",
2003, AJ, 125, 1448
"A study of the Mg II 2796.34 Å emission line in late-type normal and RS CVn stars",
2003, A&A, 408, 337
"The 100 Brightest X-Ray Stars within 50 Parsecs of the Sun",
2003, AJ 126, 1996
"Composite spectra Paper 13: 93 Leonis, a chromospherically-active binary",
2004, MNRAS, 350, 685
"Investigating Ca II emission in the RS CVn binary ER Vulpeculae using the Broadening Function Formalism",
2005, AJ, 130, 799
"Solar-Type Activity in Main-Sequence Stars",
Springer, 2005,
(Astronomy and Astrophysics Library)
"2MASS J05162881+2607387 is a Double-Lined Eclipsing Low-Mass Binary",
2005ATel..680....1B
"2MASS J05162881+2607387: A New Low-mass Double-lined Eclipsing Binary",
2006, ApJ, 651, 1155
"Photospheric and chromospheric active regions on three
single-lined RS CVn binaries",
2006, A&A, 446, 1129
"Doppler imaging of stellar surface structure - XXIII. The ellipsoidal K giant binary zeta Andromedae",
2007, A&A 463, 1071
The Wilson Bappu effect and other Ca II H and K
line parameters relationships in chromospherically active binaries
Montes D., Fernández-Figueroa M.J., De Castro E., Cornide M.,
ABSTRACT
We have found that for very active stars the emission widths, both W0
and W1, are larger than expected from previously accepted
width-luminosity relations.
The stars with strong emission intensities, IK3, and
large values of Vsin{i} seem to present
larger values of W0 than resulted from WB relation, being
the effect of the rotational velocity the most remarkable.
On the contrary, W1 is strongly influenced
by IK3 but the effect of the rotational broadening
is lesser.
We also analyse the behaviour of the Ca~II H and K line
parameters in these very active stars in relation with less active
stars and we found that the increase of W1 and IK1 with
IK3 presents a flattening for the most active stars which
is different for each value of W0.
Finally we also find a Hε
width-luminosity correlation in the stars of the sample in which this
emission line is present.
Citations
"A CaII and MgII Luminosity-Emission width data base",
1994, A&AS 108, 611
"Are the rotational axes perpendicular to the orbital planes in
the binary systems II. Synchronous log-period RS CVn stars",
1994, Acta Astron. 44, 393
"Spectroscopy of the CaII line in metal-poor red giants. II.
Northern observations",
1995, AJ 110, 405
"A critical analysis of the Wilson-Bappu relationship",
1995, 9th Cool stars
"An active K0 IV-V star and a hot white dwarf (EUVE J0702+129) in a
wide binary",
1997, A&A 318, L9
"Stellar activity and the Wilson-Bappu relation",
1997 A&A 326, 165
"Alignment of rotational axes in asynchronous late type binaries",
1997, A&A 328, 579
"Hot white dwarfs in the extreme-ultraviolet explorer survey. IV. DA white dwarfs with
bright companions",
1998, ApJ 502, 763
"Recalibration of the Wilson-Bappu Effect Using the Singly
Ionized Magnesium k Line",
1998, PASP 110, 794
"The Wilson-Bappu relation for RS CVn stars",
1999, in ASP Conf. Ser. 158,
Solar and Stellar Activity: Similarities and Differences
(meeting dedicated to Brendan Byrne, Armagh 2-4th September 1998),
C.J. Butler and J.G. Doyle, eds., in press
"The Wilson-Bappu relation for RS CVn stars",
1999, A&A 350, 635
"Catalogue and bibliography of the UV Cet-type flare stars and related objects
in the solar vicinity",
1999, A&AS 139, 555
"On the Wilson-Bappu relationship in the Mg II k line",
2001, A&A, 374, 1085
"A study of the Mg II 2796.34 Å emission line in late-type normal and RS CVn stars",
2003, A&A, 408, 337
"Evidence for Planet-induced Chromospheric Activity on HD 179949",
2003, ApJ, 597, 1092
"Spectroscopic and photometric observations of the short-period RS CVn-type
star WY Cnc",
2004, A&A, 415, 231
"Spectroscopic and photometric observations of the short-period RS CVn-type star BH Virginis",
2004, A&A, 424, 993
"Hot Jupiters and Hot Spots: The Short- and Long-term Chromospheric Activity on Stars with Giant Planets",
2005, ApJ, 622, 1075
"Investigating Ca II emission in the RS CVn binary ER Vulpeculae using the Broadening Function Formalism",
2005, AJ, 130, 799
"On the binary nature of 1RXS J162848.1-415241",
2005, ApJ, 632, 514
"Solar-Type Activity in Main-Sequence Stars",
Springer, 2005,
(Astronomy and Astrophysics Library)
"The On/Off Nature of Star-Planet Interactions",
2007, ApJ,in press
Excess Hα emission in chromospherically active
binaries
Montes D., Fernández-Figueroa M.J., De Castro E.,
Cornide M.
ABSTRACT
The behaviour of the excess Hα emission
as a function of the rotation has been analyzed.
A slight decline toward longer rotational periods, P_rot,
and larger Rossby numbers, R_0, is present
in agreement with previous
results using others activity indicators.
We have compared the derived excess Hα emission fluxes with
those obtained in the CaII K and Hε lines
finding that a good correlation exits
between these three chromospheric activity indicators.
The Hα losses seem to be more important
than CaII K losses
for cooler stars, in fact all the system with
Hα emission above the
continuum are cooler than 5000 K.
Correlations with other activity indicators,
(CIV in the transition region, and X-rays in the corona)
indicate that the exponents of the power-law
relations increase with the formation
temperature of the spectral features.
Citations
"Multiwavelength observations of two moderate rotation RS CVn systems:
V815 Her, IM Peg",
1996, AJ 111, 1356
"Environments of active close binaries I. ER Vulpeculae" ,
1997, A&A 318, 60
"Environments of active close binaries II. GK Hydrae, TY Pyxidis" ,
1997, A&A 319, 211
A new H alpha. survey of chromospherically active binaries (II) ,
1997, Ap&SS 246, 39
"Hα emission in the chromospherically
active binari sigma2 Coronae Borealis (TZ CrB)",
1997, A&A 320, 101
"Quantitative Spectroscopic Criteria for the Classification of Pre-main
Sequence Low-mass Stars"
1997, A&A 321, 492
"The rotation period of a very low-mass star in α
Persei"
1997, MNRAS 286, L17
"The Age-Mass Relation for Chromospherically Active Binaries. II. Lithium
depletion in dwarfs components",
1997, A&A 326, 780
"Chromospherically active stars. XVII. The double-lined binary 54 Cam
= AE Lyn",
1998, AJ 115, 1153
"BD +05 deg706: A New Member of the Class of ``Cool Algols''",
1998, AJ 115, 2028
"Spectroscopic binary orbits from photoelectric radial velocities - Paper
142: xi Ursae Majoris",
1998, Observatory 118 (1146), 273
"Time-resolved spectroscopy of RS Canum Venaticorum short-period systems.
II. RT Andromedae, WY Cancri, and XY Ursae Majoris",
1999,
AJ 118, 1015
"Catalogue and bibliography of the UV Cet-type flare stars and related
objects in the solar vicinity",
1999, A&AS 139, 555
"AR Lacertae: Hα chromospheric emission and radial velocities from
long-term optical spectroscopy",
2000, A&A 358, 1007
"Radio, X-ray, and EUV Coronal Variability of the Short-Period RS CVn
Binary sigma^2 Coronae Borealis",
2000,
ApJ, 554, 953
"Coronal X-Ray Emission from the Stellar Companions to Transiently Accreting
Black Holes",
2000, ApJ, 541, 908
"Statistics of by Draconis Variables",
Astronomy Report, 2000, Vol 44, Iss 10, pp 696-700
"Spectroscopic and photometric observations of the short-period RS CVn
star RT And",
2001, A&A 378, 102
"Hα Spectroscopy and BV Photometry of RT Lacertae",
2002, A&A, 388, 298
"The Structure of Stellar Coronae in Active Binary Systems",
2003, ApJS, 145, 147
"Spectroscopic and photometric observations of the short-period RS CVn-type
star CG Cyg",
2003, A&A, 400, 623
"Spectroscopic and photometric observations of the short-period RS CVn-type
star ER Vulpeculae",
2003, A&A, 404, 611
"Spectroscopic and photometric observations of the short-period RS CVn-type
star WY Cnc",
2004, A&A, 415, 231
"Further Results Of Tio-Band Observations Of Starspots",
2004, AJ, 128, 1802
"Spectroscopic and photometric observations of the short-period RS CVn-type star BH Virginis",
2004, A&A, 424, 993
"Spectroscopic and photometric observations of the short-period RS CVn-type star UV Piscium",
2005, AJ, 129, 1084
"Solar-Type Activity in Main-Sequence Stars",
Springer, 2005,
(Astronomy and Astrophysics Library)
"Plage and flare Activity of the RS CVn-type Star UX Arietis during 2001-2002",
2005, Coronal and Stellar Mass Ejections
Proceedings IAU Symposium No. 226, 2005
K. P. Dere, J. Wang & Y. Yan, eds., p. 501
"A compact flare eclipsed in the corona of SV Cam",
2006, A&A, 445, 673
"A Comparative Study of Flaring Loops in Active Stars",
2006, ApJ, 164, 173
"On the distance of GRO J1655-40",
2006, A&A, 464, L61
"Ha and the Ca II H and K lines as activity proxies for late-type stars",
2007, A&A, 469, 309
Excess Hα emission
in chromospherically active binaries: the spectroscopic survey
Montes D., Fernández-Figueroa M.J., De Castro E., Cornide M.
Citations
"The Complex Hα Profile of AE Aqr" ,
1995, Cape Workshop on Magnetic cataclysmic variables; ASP Conf. S. 85, 359
"Environments of active close binaries II. GK Hydrae, TY Pyxidis" ,
1997, A&A 319, 211
A new Hα. survey of chromospherically active binaries (II) ,
1997, Ap&SS 246, 39
"The fundamental parameters, chromospheric activity and magnetic field measurements of HR 5553",
1998, Ap&SS 257, 259
"Spectroscopic binary orbits from photoelectric radial velocities - Paper 142: xi Ursae Majoris",
Observatory 118 (1146): 273-298 Oct 1998
"Catalogue and bibliography of the UV Cet-type flare stars and related objects
in the solar vicinity",
1999, A&AS 139, 555
"Time-series photometric spot modeling
IV. The multi-periodic K5Ve binary V833 Tauri",
2001, A&A 372, 119
"Chromospheric activity on the RS CVn-type binary UX Arietis",
2002, A&A 388, 889
"A study of the Mg II 2796.34 Å emission line in late-type normal and RS CVn stars",
2003, A&A, 408, 337
"A period investigation of two chromospherically active binary stars: RT Coronae Borealis and PW Herculis",
2003, NewA, 8, 457
"Photospheric and chromospheric active regions on three
single-lined RS CVn binaries",
2006, A&A, 446, 1129
Application of the spectral subtraction technique to the
Ca II H & K and Hε lines in a sample of chromospherically
active binaries
Montes, D., De Castro, E., Fernández-Figueroa, M.J., Cornide, M.
ABSTRACT
The emissions arising from each
individual star were obtained when it was possible to deblend the
contribution of both components.
The Ca II line profiles corresponding to different seasons and orbital
phases are analysed in order to determine
the contribution of each component and to study the chromospheric
activity variations.
Citations
"Hα emission in the
chromospherically active binari sigma2 Coronae Borealis (TZ CrB)",
1997, A&A 320, 101
"Catalogue and bibliography of the UV Cet-type flare stars and related objects
in the solar vicinity",
1999, A&AS 139, 555
"A study of the Mg II 2796.34 Å emission line in late-type normal and RS CVn stars",
2003, A&A, 408, 337
Mg II chromospheric radiative loss rates in cool active and quiet stars",
2005, A&A, 430, 303
"Solar-Type Activity in Main-Sequence Stars",
Springer, 2005,
(Astronomy and Astrophysics Library)
The behaviour of the excess Ca II H & K and Hε emissions
in chromospherically active binaries
Montes, D., Fernández-Figueroa, M.J., Cornide, M., De Castro, E.,
ABSTRACT
Citations
"The Age-Mass Relation for Chromospherically Active Binaries. II.
Lithium depletion in dwarfs components",
1997, A&A 326, 780.
"Long-term monitoring of active stars
VII. UBV(RI)c photometry collected in March 1991",
1998, A&AS 127, 207
"Long-term monitoring of active stars
VIII. UBV(RI)c photometry collected in March 1992",
1998, A&AS 131, 321
"Fixed-phase observations of RS Cvn and BY Dra systems",
1998, AJ 115, 2571
"Metallicity effects on the chromospheric activity-age relation
for late-type dwarfs",
1998, MNRAS 298, 332
"A period study of the RS CVn-type binary ER Vulpeculae",
1998, Ap&SS 257, 1
"The fundamental parameters, chromospheric activity and magnetic field measurements of HR 5553",
1998, Ap&SS 257, 259
"The photospheric filling factor of the active binary II Pegasi",
1999 A&A 352, 189
"Long-term monitoring of active stars. IX. Photometry collected in 1993",
2001, A&A 367, 910
"Photometric and TiO modelling of the starspots
on AG Dor and HU Vir"
2002, A&A 381, 517
"First spectra of the W UMa system V524 Monocerotis",
2005, A&A 429, 625
"Investigating Ca II emission in the RS CVn binary ER Vulpeculae using the Broadening Function Formalism",
2005, AJ, in press
"Solar-Type Activity in Main-Sequence Stars",
Springer, 2005,
(Astronomy and Astrophysics Library)
Simultaneous Hα, Na I D1, D2,
and He I D3 observations of a flare on the RS CVn system UX Ari
Montes, D., Sanz-Forcada, J. Fernández-Figueroa, M.J., Lorente, R.,
ABSTRACT
Citations
"Photospheric and chromospheric activity in the late-type giant
component of the evolved binary system HD 185510"
1998, A&A 333, 205
"The role of non-thermal electrons in the hydrogen and calcium
lines of stellar flares"
2001, MNRAS 326, 943
"Hydroxyl 1.563 Micron Absorption from Starspots on Active Stars"
2001, AJ 122, 1954
"Quiescent and Flaring Structure in RS CVn stars",
2002, ApJ, 570, 799
"Hα flares from V404 Cyg in quiescence"
2002, MNRAS, 330, 1009
"Chromospheric activity on the RS CVn-type binary UX Arietis",
2002, A&A 388, 889
"A study of the Mg II 2796.34 Å emission line in late-type normal and RS CVn stars",
2003, A&A, 408, 337
"Plage and flare Activity of the RS CVn-type Star UX Arietis during 2001-2002",
2005, Coronal and Stellar Mass Ejections
Proceedings IAU Symposium No. 226, 2005
K. P. Dere, J. Wang & Y. Yan, eds., p. 501
Hα emission fluxes and
lithium abundances of low mass stars in the young open cluster IC4665
Martín E.L., Montes, D.
-- (accepted May 1996)
ABSTRACT
Citations
"Quantitative Spectroscopic Criteria for the Classification
of Pre-main Sequence Low-mass Stars"
1997, A&A 321, 492
"Common envelope evolution and Li in V471 Tauri"
1997, A&A 326, 731
"Lithium in Young Clusters and Pre-Main Sequence Stars"
1997, ``Cool Stars in
Clusters and Associations: Magnetic Activity and Age Indicators'', Palermo,
MemSait Vol. 68. No. 4 - 1997, edited by G. Micela, R. Pallavicini and S. Sciortino
"X-ray Activity in the open cluster IC 4665"
1998, ApJ 501, 624
"Lithium in ROSAT-discovered Candidate Members in the Alpha Persei
Cluster
1998, A&A 333, 591
"A lithium-survey for pre-main sequence stars in the Upper Scorpius OB association"
1998, A&A 333, 619
"A Search for Very Low-mass Stars and Brown Dwarfs in the Young sigma Orionis Cluster"
1999, ApJ 521, 671
"Lithium depletion in open clusters",
1999, in ASP Conf. Ser., "Stellar clusters and associations: convection, rotation, and dynamos", (Second
"Three-Islands" Euroconference) (May 25 - 28, 1999, Mondello, Palermo, Sicily, Italy), R. Pallavicini, G. Micela and S.
Sciortino eds.
"Brown Dwarfs and Very Low Mass Stars:
Toward a New Age Scale for Young Open Clusters",
1999, Astrophysics and Space Science 263, 239,
in: "Highlights of Spanish Astrophysics",
Proceedings of the
III Scientific Meeting of the Spanish Astronomical Society (SEA)
(held in La Laguna, Tenerife, Spain, September 21-24, 1998),
eds. J. Gorgas & J. Zamorano
"Evolution Of The Lithium Abundances Of Solar-Type Stars. IX.
High-Resolution Spectroscopy of Low-Mass Stars in NGC 2264",
1999, AJ 118, 1301
"Accretion-Induced Lithium Line Enhancements in Classical
T Tauri Stars: RW Aur"
2000, ApJ 532, 474
"Light Element Abundances in Cool Stars and Brown Dwarfs",
2000, in ASP Conf. Ser.,
in ``Cool Stars, Stellar Systems and the Sun. Eleventh Cambridge Workshop.,
R. García López, R. Rebolo, M.R. Zapatero Osorio (eds.), (in press)
"Membership, lithium, and metallicity in the young open clusters
IC 2602 and IC 2391: enlarging the sample",
2001, A&A, 372, 862
"On the dispersion in lithium and potassium among late-type
stars in young clusters: IC 2602",
2001, A&A 377, 512
"Galactic Chemical Evolution of Lithium: Interplay between
Stellar Sources",
2001, ApJ 559, 909
"Li abundance in Pop I stars",
IAU SYMP (198): 269-278, 2000
"The evolution of lithium depletion in young open clusters: NGC 6475",
2003, A&A 407, 289
"Late main-sequence evolution of lithium and beryllium",
2003, A&A 408, 1037
"Light element evolution resulting from WMAP data",
2003, MNRAS 346, 295
"Lithium Abundances of the Local Thin Disk Stars",
2004, MNRAS, 349, 757
"Pre-main-sequence Lithium Depletion",
2004, invited review at "Chemical abundances and mixing in stars in the Milky Way and its satellites",
eds. L. Pasquini, S. Randich. ESO Astrophysics Symposium (Springer-Verlag)
"A near-infrared survey for new low-mass members in Alpha Per",
2005, A&A, 436, 853
"Time scales of Li evolution: a homogeneous analysis of open clusters from ZAMS to late-MS",
2005, A&A, 442, 615
"Spectroscopic abundance analysis of dwarfs in young open cluster IC 4665",
2005, ApJ, 635, 608
"A study of the young open cluster Collinder 359",
2005AN....326.1001L
"Exploring the Lower Mass Function in the young open Cluster IC 4665",
2006, A&A, 448, 189
"Oxygen Abundance of Open Cluster Dwarfs",
2007, ApJ, 660, 712
"Detection of the lithium depletion boundary in the young open cluster IC 4665",
2008, A&A, 479, 141
Library of high and mid-resolution spectra in the
CaII H & K, Hα,
Hβ, and
NaI D1,
D2, and HeI D3
line regions of F, G, K and M field stars
Montes D., Martín E.L., Fernández-Figueroa M.J., Cornide M., De Castro E.,
(accepted September 1996)
ABSTRACT
Citations
"Weak and post-T Tauri stars around B-type members of the Scorpius-Centaurus
OB association"
1998, AJ 115, 351
"Discovery of seven nearby T Tauri stars in the TW Hydrae Association",
1998, Bull. American Astron. Soc., 192, #10.07
"Spectroscopic classification of X-ray selected stars in the rho Ophiuchi
star-forming region and vicinity"
1998, MNRAS 300, 733
"Spectroscopy of stars in the galaxy M 81"
1998, AstL 24, 507
"Atmosphere parameters of four K-giants obtained by spectrum fitting"
1999, A&AS 138, 47
"A Test of Pre-Main-Sequence Evolutionary Models across the Stellar/Substellar
Boundary Based on Spectra of the Young Quadruple GG Tauri"
1999, ApJ 520, 811
"Photometric observations of weak-line T Tauri stars . II. WTTS in Taurus-Auriga,
Orion and Scorpius OB2-2"
2000, Astron. Astrophys. Suppl. Ser. 145, 187
"Optical follow-up of ROSAT discovered candidate members of the open cluster
Coma Berenices"
2000, A&A 363, 958
"Observational Constraints on the Formation and Evolution of Binary Stars"
2001, ApJ 556, 265
"EXPORT: Spectral classification and projected rotational velocities of
Vega-type and pre-main sequence stars"
2001, A&A 378, 116
"The lithium depletion boundary and the age of NGC 2547" ,
2003, MNRAS, 342, 651
"Cool stars in NGC 2547 and pre-main-sequence lithium depletion" ,
2003, MNRAS, 343, 1271
"Gravity Indicators in the Near-Infrared Spectra of Brown Dwarfs" ,
2003, ApJ, 593, 1074
"A study of the two northern open clusters NGC 1582 and NGC 1663",
2003, A&A, 407, 527
"Library of flux-calibrated echelle spectra of southern late-type dwarfs with different activity levels",
2004, A&A, 414, 699
"HD 34700 is a T Tauri multiple system",
2005, A&A, 434, 671
"On the Ages of Exoplanet Host Stars",
2005, A&A, in press
"Orbit, Dynamical Mass, and MK Type of Visual Binary WOR 2",
2005, AJ, 130, 2847
"Long-Term V-Band Monitoring of the Bright Stars of M33 at the Wise Observatory",
2006, MNRAS, 370, 1429
"U Geminorum: a test case for orbital parameters determination",
2007, AJ, 134, 262
"The Rapid Outbursting Star GM Cep: An EX-or in Tr 37?",
2007, ApJ, in press
Multiwavelength optical observations of chromospherically active binary
systems.
Montes D., Fernández-Figueroa M.J., De Castro E., Sanz-Forcada J.,
(accepted December 1996)
I. Simultaneous Hα,
NaI D1, D2,
and HeI D3 observations
ABSTRACT
Citations
"The fundamental parameters, chromospheric activity and magnetic field measurements of HR 5553",
1998, Ap&SS 257, 259
"Utrecht Echellete Spectroscopy of a flare in VB8"
1999, MNRAS 302, 59
"Astrophysics in 1998",
1999, PASP 111, 385
"Optical spectroscopy of X-ray sources in the old open cluster M 67",
1999, A&A 347, 866
"The active RS Canum Venaticorum binary II Pegasi. III.
Chromospheric emission and flares in 1994-1996",
1999, A&A 349, 863
"Long Term Halpha Spectroscopy of AR Lac",
2000, in ASP Conf. Ser., The 11th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun , (Challenges for the
New Millennium), (October 4th - 8th, 1999, Puerto de la Cruz, Tenerife, Spain)
"AR Lacertae: Halpha chromospheric emission and radial velocities
from long-term optical spectroscopy",
2000, A&A 358, 1007
"Chromospheric two-component NLTE modelling of the binary system
V 711 Tau = HR 1099",
2000, A&A 362, 683
"Time series analysis of V815 Herculis photometry between 1984 and 1998",
2000, A&A 362, 223
"Long-term monitoring of active stars. IX. Photometry collected in 1993",
2001, A&A 367, 910
"Time-series photometric spot modeling
IV. The multi-periodic K5Ve binary V833 Tauri",
2001, A&A 372, 119
"New Physical Elements of HR 7428 and its Hα Behaviour",
2001, A&A 375, 100
"BVR photometry and Hα spectroscopy of RS CVn type binary
MM Herculis",
2001, A&A, 376, 966
"Chromospheric activity on the RS CVn-type binary UX Arietis",
2002, A&A 388, 889
"Echelle observations of chromospheric activity in post-common-envelope binaries",
2002, MNRAS 335, 593
"The Structure of Stellar Coronae in Active Binary Systems",
2003, ApJS, 145, 147
"The Complex Ha Line Profile of the Bright Companion to PSR J1740-5340 in NGC 6397",
2003, ApJ, 589, L41
"The Coronae of AR Lac",
2003, ApJ, 595, 1131
"A study of the Mg II 2796.34 Å emission line in late-type normal and RS CVn stars",
2003, A&A, 408, 337
"Starspot activity on the RS CVn-type binary II Pegasi during 1999-2001",
2003, A&A 405, 763
"The chemical composition of the peculiar companion to the millisecond pulsar in NGC 6397",
2003, 412, 829
"The weak-line T Tauri star V410 Tau - II. A flaring star",
2004, A&A 427, 263
"Optical and EUV observations of solar flare kernels",
2005, A&A, 444, 593,
"Photospheric and chromospheric active regions on three
single-lined RS CVn binaries",
2006, A&A, 446, 1129
Multiwavelength optical observations of chromospherically active binary
systems.
Montes D., Sanz-Forcada J., Fernández-Figueroa M.J., De Castro E., Poncet
A. (accepted July 1997)
II. EZ Pegasi
ABSTRACT
Citations
"Empirical calibration of the near-infrared Ca II triplet -
I. The stellar library and index definition",
2001, MNRAS 326, 959
"On the binary nature of 1RXS J162848.1-415241",
2005, ApJ, 632, 514
Library of high-resolution UES echelle spectra
of F, G, K and M field dwarf stars
Montes D., Martín E.L., (accepted August 1997)
ABSTRACT
Citations
"Utrecht Echellete Spectroscopy of a flare in VB8"
1998, MNRAS 302, 59
"Doppler imaging of cool dwarf stars"
1998, in Euroconference on Very-Low Mass Stars and Brown Dwarfs,
La Palma May 1998,
Cambridge University Press, (in press)
"High-speed optical spectroscopy of a cataclysmic variable
wind: BZ Camelopardalis"
1998, AJ 115, 286
"Discovery of seven T Tauri stars and a brown dwarf candidate in
the nearby TW Hydrae Association"
1999, ApJ 512, L63
"Probing the NaI D and KI"
lambda 7699 Resonance Lines Sensitivity to Background Opacity in Late-type Stars"
1999, A&A 345, 915
"Optical spectroscopy of X-ray sources in the old open cluster M 67",
1999, A&A 347, 866
"High resolution spectroscopy over ll 8500-8750 Å for GAIA. I. Mapping the MKK classification system",
1999, A&AS 137, 521
"The TW Hydrae Association: Discovery of T Tauri Star Members Near HR 4796",
2001, ApJ 549, L233
"Empirical calibration of the near-infrared Ca II triplet -
I. The stellar library and index definition",
2001, MNRAS 326, 959
"Echelle observations of chromospheric activity in post-common-envelope binaries",
2002, MNRAS 335, 593
"Variability of Southern T Tauri Stars (VASTT). III. The Continuum Flux Changes of the TW Hydrae Bright Spot",
2002, ApJ 580,343
"The eclipsing millisecond pulsar PSR J1740-5340 and its red straggler companion",
2003, A&A, 397, 237
"High resolution spectroscopy over
lambda 8500-8750 A for GAIA. IV. Extending the cool MK stars sample",
2003, A&A 406, 995
"HD 34700: A new T Tauri double-lined spectroscopic binary",
2003, A&A 408, L29
"Magnetic activity in HD 111456, a young F5-6 main-sequence star",
2004, A&A, 413, 657
"Library of flux-calibrated echelle spectra of southern late-type dwarfs with different activity levels",
2004, A&A, 414, 699
"Spectroscopic survey of the Galaxy with Gaia I. Design and performance of the Radial Velocity Spectrometer",
2004, MNRAS, 354, 1223
"High-Dispersion Spectra Collection of Nearby F--K Stars at Okayama Astrophysical Observatory:
A Basis for Spectroscopic Abundance Standards",
2005, PASJ 57, 13
"On the Ages of Exoplanet Host Stars",
2005, A&A, in press
"The IAC online catalog for M-, L- and T-type dwarfs",
2005, AN 326, 1026
"Kinematic structure in the young Sigma Orionis association",
2006, MNRAS, in press
"Oxygen Abundance of Open Cluster Dwarfs",
2007, ApJ, 660, 712
Detection of Li I enhancement during a long-duration stellar flare
Montes D., Ramsey L.W., (accepted October 1998)
ABSTRACT
Citations
"Abundance Anomalies in stars" ,
1998,
The 1998 STScI May Symposium
"Unsolved Problems in Stellar Evolution"
"Stellar Flares: Theory and Observations" ,
1999, in ASP Conf. Ser. 158, Solar and Stellar Activity: Similarities and Differences (meeting dedicated to Brendan Byrne, Armagh 2-4th September 1998)
C.J. Butler and J.G. Doyle, eds.
"A Role of Large-Scale Magnetic Fields in Stellar Activity
Phenomena" , 2000, in ASP Conf. Ser.,
The 11th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun,
(Challenges for the New Millennium),
(October 4th - 8th, 1999, Puerto de la Cruz, Tenerife, Spain)
"The Quiescent X-ray Emission of X-ray Novae and the Coronal
Emission of Late-Type Stars",
2000, Astronomy Reports, Volume 44, Issue 12, pp.804-814
"On 7Li Enrichment by Low-Mass Metal-Poor Red
Giant Branch Stars",
2000, ApJ 535, L115
"Lithium",
2000, Physics Reports -REVIEW SECTION OF PHYSICS LETTERS,
Vol 333, Iss 1-6, pp 449-469
"Echelle observations of chromospheric activity in post-common-envelope binaries",
2002, MNRAS 335, 593
"Li (and other light elements) and stellar activity",
2002, Astron. Nachr./AN 323, 325
"6Li in the atmosphere of GJ 117",
2005, ApJ, 632, L127
"Optical and EUV observations of solar flare kernels",
2005, A&A, 444, 593,
Is 6-Li in metal-poor halo stars produced in situ by solar-like flares?,
2007, A&A, 469, 265
Optical and UV observations of a strong flare
in the young, single K2-dwarf LQ Hya
D. Montes, S.H. Saar, A. Collier Cameron, Y.C. Unruh
ABSTRACT
Citations
"Multi-site Observations of Surface Structures on
AB Doradus in 1994 November" ,
1999, MNRAS 308, 493
"Surface Differential Rotation and Prominences of the Lupus
Post T-Tauri Star RX J1508.6-4423" ,
2000, MNRAS, Vol 316, Iss 3, pp 699-715
"Quiescent and flare analysis for the chromospherically active star Gl 355 (LQ Hya)" ,
2001, A&A, 371, 973
"Extensive serendipitous X-ray coverage of a flare star with ROSAT" ,
2001, MNRAS 323, 577
"The role of non-thermal electrons in the hydrogen and calcium
lines of stellar flares",
2001, MNRAS 326, 943
"Observations and modelling of a large optical flare on AT Microscopii",
2002, A&A 383, 548
"Echelle observations of chromospheric activity in post-common-envelope binaries",
2002, MNRAS 335, 593
"Starspots and active regions on the emission red dwarf star
LQ Hydrae",
2002, A&A 396, 203
"The Structure of Stellar Coronae in Active Binary Systems",
2003, ApJS, 145, 147
"Doppler imaging of stellar surface structure - XXII. Time-series mapping of the young rapid rotator LQ Hydrae",
2004, A&A, 417, 1047
"Detection of red line asymmetries in LHS 2034",
2005, A&A, 436, 677
"Optical Spectroscopy of a Flare on Barnard's Star",
2006, ApJ, 118, 227
"Solar-Type Activity in Main-Sequence Stars",
Springer, 2005,
(Astronomy and Astrophysics Library)
"Optical and EUV observations of solar flare kernels",
2005, A&A, 444, 593,
"Accretion Disks around Young Stars: Lifetimes, Disk Locking and Variability",
2006, ApJ, in press,
Library of medium-resolution Fiber Optic Echelle spectra
of
D. Montes, L.W. Ramsey, A.D. Welty (accepted November 1998)
F, G, K and M field dwarfs to giants stars
ABSTRACT
Citations
"A Na I Absorption Map of the Small-Scale Structure in the Interstellar Gas toward M15" ,
1999, ApJ 520, L103
"Observations and Atmospheric Parameters of Super-Metal-rich
Candidates" ,
2000, PASP 112, 1455
"Small-Scale Interstellar Na I Structure toward M92" ,
2001, ApJ, 552, L73
"Empirical calibration of the near-infrared Ca II triplet -
I. The stellar library and index definition",
2001, MNRAS 326, 959
"Long-term monitoring of active stars. X. Photometry collected in 1994",
2003, A&A, 400, 659
"STELIB: A library of stellar spectra at R ~ 2000",
2003, A&A, 402, 433
"A study of the two northern open clusters NGC 1582 and NGC 1663",
2003, A&A, 407, 527
"Orbit and System Mass for the Visual Binary WDS 23186+6807AB",
2003, AJ 126, 1522
"Library of flux-calibrated echelle spectra of southern late-type dwarfs with different activity levels",
2004, A&A, 414, 699
"A spectral atlas of F and G stars",
2004, CHINESE JOURNAL OF ASTRONOMY AND ASTROPHYSICS 4 (3): 279-283
"TrES-1: The Transiting Planet of a Bright K0 V Star",
2004, ApJ, 613, L153
"Spectroscopic survey of the Galaxy with Gaia I. Design and performance of the Radial Velocity Spectrometer",
2004, MNRAS, 354, 1223
"A study of two post-common envelope binary systems",
2005, MNRAS, 359, 315
"On the Ages of Exoplanet Host Stars",
2005, A&A, in press
Multiwavelength optical observations of chromospherically active binary
systems.
Montes D., M.J. Fernández-Figueroa, E. De Castro
M. Cornide, A. Latorre, J. Sanz-Forcada,
III. High resolution echelle spectra from Ca II H&K to Ca II IRT
ABSTRACT
Very broad wings have been found in the subtracted Hα profile
of the very active star HU Vir.
These profiles are well matched using a two-component
Gaussian fit (narrow and broad) and the broad component
can be interpreted as arising from microflaring.
Red-shifted absorption features in the Hα line
have been detected in several systems and
excess emission in the blue wing of FG UMa was also detected.
These features indicate that several dynamical processes,
or a combination of them, may be involved.
Using the E(Hα)/E(Hβ) ratio as a diagnostic
we have detected prominence-like extended material viewed off the limb
in many stars of the sample, and prominences viewed against the disk
at some orbital phases in the dwarfs OU Gem and BF Lyn.
The He I D_3 line has been detected
as an absorption feature in mainly all the giants of the sample.
Total filling-in of the He I D_3,
probably due to microflaring activity,
is observed in HU Vir.
Self-absorption with red asymmetry
is detected in the Ca II H & K lines of the giants
12 Cam, FG UMa and BM CVn.
All the stars analysed show clear
filled-in Ca II IRT lines or even notable emission reversal.
The small values of the E(8542)/E(8498) ratio we have found
indicate Ca II IRT emission arises from plage-like regions.
Orbital phase modulation of the chromospheric emission
has been detected in some systems, in the case of
HU Vir evidence of an active longitude area has been found.
Citations
"New Physical Elements of HR 7428 and its Hα Behaviour",
2001, A&A 375, 100
"Hydroxyl 1.563 Micron Absorption from Starspots on Active Stars"
2001, AJ 122, 1954
"Radial velocities and orbital solution of the active binary
star FG Ursae Majoris"
2002, IBVS, Vol. 5201, 5227
"Chromospheric activity on the RS CVn-type binary UX Arietis",
2002, A&A 388, 889
"Chromospherically active stars. XXI.
The giant, single-lined binaries HD 89546 and HD 113816",
2002, AJ 124, 1064
"Starspots and active regions on the chromospherically active binary MS Ser,
2003, A&A 403, 205
"The Complex Ha Line Profile of the Bright Companion to PSR J1740-5340 in NGC 6397",
2003, ApJ, 589, L41
"A study of the Mg II 2796.34 Å emission line in late-type normal and RS CVn stars",
2003, A&A, 408, 337
"The chemical composition of the peculiar companion to the millisecond pulsar in NGC 6397",
2003, 412, 829
"Magnetic activity in HD 111456, a young F5-6 main-sequence star",
2004, A&A, 413, 657
"Further Results Of Tio-Band Observations Of Starspots",
2004, AJ, 128, 1802
"The Ca II Infrared Triplet as a stellar activity diagnostic
I. Non-LTE photospheric profiles and definition of the R_IRT indicator",
2005, A&A, 430, 669
"Solar-Type Activity in Main-Sequence Stars",
Springer, 2005,
(Astronomy and Astrophysics Library)
"Plage and flare Activity of the RS CVn-type Star UX Arietis during 2001-2002",
2005, Coronal and Stellar Mass Ejections
Proceedings IAU Symposium No. 226, 2005
K. P. Dere, J. Wang & Y. Yan, eds., p. 501
"The search for extrasolar planets: Study of line bisectors and its relation with precise radial
velocity measurements",
2006, PhD Thesis,
(Universita degli Studi di Padova)
"On the distance of GRO J1655-40",
2006, A&A in press
Late-type stars members of young stellar kinematic groups.
I. Single stars
Montes D., López-Santiago J., Gálvez M.C., Fernández-Figueroa M.J.,
De Castro E., Cornide M.,
ABSTRACT
In this paper we have compiled a preliminary list
of single late-type stars
possible members of some of these young stellar kinematic groups.
Stars have been selected from previously established members of
stellar kinematic groups based in photometric and kinematic properties
as well as from candidates based in other criteria as their
level of chromospheric activity, rotation rate, lithium abundance.
Precise measurements of proper motions and parallaxes taken from
Hipparcos Catalogue, as well as from Tycho-2 Catalogue,
and published radial velocity measurements
are used to calculate Galactic space motions (U, V, W)
and apply the Eggen's kinematic criteria
in order to determine the membership of the selected stars to the
different groups.
Additional criteria using age-dating methods for late-type stars
will be applied in forthcoming papers of this series.
A further study of the list of stars compiled here
could lead to a better understanding of the chromospheric activity
and their age evolution as well as of the
star formation history in the solar neighbourhood.
In addition, these stars are also potential search targets
for direct imaging detection of sub-stellar companions
Citations
"Kinematics of Hipparcos Visual Binaries. II. Stars with Ground-Based Orbital Solutions",
2002, Baltic Astronomy, v.11, p.153-203
"FR Cnc = BD +16 1753 - a young active main-sequence star",
2002, IBVS, 5351, 1
"Long-term monitoring of active stars. X. Photometry collected in 1994",
2003, A&A, 400, 659
"The field brown dwarf LP 944-20 and the Castor moving group",
2003, A&A, 400, 297
"Nearby young stars",
2003, A&A, 399, 983
"Stellar kinematic groups II. A Re-Examination of
the Membership, Activity, and Age of the Ursa Major Group",
2003, AJ, 125, 1980
"New Photoelectric Photometry of the Young Star LO Pegasi",
2003, IBVS, 5390, 1
"Astrophysics in 2002",
2003, PASP, 115, 514
"A New Multiple Stellar System in the Solar Neighborhood",
2003, AJ 126, 918
"The 100 Brightest X-Ray Stars within 50 Parsecs of the Sun",
2003, AJ 126, 1996
"Age Dependence of the Vega Phenomenon: Observations",
2003, ApJ, 598, 636
"A survey of 10-µm silicate emission from dust around young sun-like stars",
2004, New Astronomy, 9, 33
"Ten-Micron Observations of Nearby Young Stars",
2004, ApJ, 600, 435
"HD 77407 and GJ 577: two new young stellar binaries detected with the Calar Alto Adaptive Optics system ALFA",
2004, A&A, 417, 1031
"A Sub-Millimeter Search of Nearby Young Stars for Cold Dust: Discovery of Debris Disks around Two Low-Mass Stars",
2004, ApJ, 608, 526
"Kinematics of chromospherically active binaries and evidence of an orbital period decrease in
binary evolution",
2004, MNRAS, 349, 1069
"Dynamical Masses of the Binary Brown Dwarf GJ 569Bab",
2004, ApJ, 615, 958
"The AB Doradus Moving Group",
2004, ApJ, 613, L65
"Young stars near the Sun",
2004, ARA&A, Vol. 42, 685
"On Ca II Emission as an Indicator of the Age of Young Stars",
2004, ApJ, 614, L125
"Dynamical Masses of the Binary Brown Dwarf GJ 569Bab",
2004, ApJ, 615, 958
"Initial Results from the Palomar Adaptive Optics Survey of Young Solar-Type Stars:
A Brown Dwarf and Three Stellar Companions",
2004, ApJ, 617, 1330
"Differential Rotation of the Active G5 V Star kappa1 Ceti: Photometry from the MOST Satellite",
2004, PASP 116, 1093
"Kinematic peculiarities of Gould Belt stars",
2004, Astronomy Letters, Vol. 30, Issue 11, p.785
"Signs for Heavy Bombardment in Debris Disks",
2004, ASP Conference Series, Vol. 324, p.121
"High-Resolution Spectroscopy of some Active Southern Stars",
2005, PASA 22, 29
"Local kinematics of K and M giants from Coravel/Hipparcos/Tycho-2 data.
Revisiting the concept of superclusters",
2005, A&A, 430, 165
"Kinematics of W Ursae Majoris type binaries and evidence of the two types of formation",
2005, MNRAS, 357, 497
"The prospects for finding brown dwarfs in eclipsing binary systems and measuring brown dwarf properties",
2005, PASP, 117, 173
"Identification of a complete sample of northern ROSAT All-Sky Survey X-ray sources. VIII. The late-type stellar component
",
2005, A&A, 433, 151
"Evolution of the Solar Activity over Time and Effects on Planetary Atmospheres: I. High-energy Irradiances (1-1700 A)",
2005, ApJ, 622, 680
"Orbits of new Hipparcos binaries. I",
2005, A&A, 433, 591
"A search for hot massive extrasolar planets around nearby young stars with the adaptive optics system NACO",
2005, ApJ, 625, 1004
"Doppler imaging of Speedy Mic using the VLT, Fast spot evolution on a young K-dwarf star",
2005, A&A 435, 261
"GU Boo: A New 0.6 Msun Detached Eclipsing Binary",
2005, ApJ, 631, 1120
"The dM4.5e star G124-62 and its binary L dwarf companion DENIS-P J1441-0945: Common proper motion, distance, age, and masses",
2005, A&A 440, 967
"Optical and X-ray studies of chromospherically active stars: FR Cancri, HD 95559 and LO Pegasi",
2005, AJ 130, 1231
"The highly spotted photosphere of the young rapid rotator Speedy Mic",
2005, MNRAS, 364, 137
"Expansion of the TW Hydrae association and the encounter with Vega",
2005, MNRAS, 362, 1109
"An Infrared coronagraphic survey for substellar companions",
2005, AJ, 130, 1845
"The N2K Consortium. IV. New temperatures and metallicities for 100,000+ FGK dwarfs",
2005, ApJ, 638, 1004
"The field of IC 2602: Strömgren-Hβ photometry approach",
2005, Astronomische Nachrichten, 326, 738
"Spectral synthesis analysis and radial velocity study of the northern F-, G-, and K-type flare-stars",
2006, MNRAS, 365, 1050
"A Spitzer Study of Dusty Disks around Nearby, Young Stars",
2005, ApJ, 634, 1372
"A Massive Planet to the Young Disc Star HD 81040",
2005, A&A, 449, 417
"Mass loss and orbital period decrease in detached chromospherically active binaries",
2006, MNRAS, 366, 1511
"Angular Differential Imaging: a Powerful High-Contrast Imaging Technique",
2006, ApJ, 641, 556
"First Scattered Light Images of Debris Disks around HD 53143 and HD 139664",
2006, ApJ, 637, L57
"Finding benchmark brown dwarfs to probe the IMF as a function of time",
2006, MNRAS, 368, 1281
"Nearby debris disk systems with high fractional luminosity reconsidered",
2006, ApJ, 644, 525
"A Comparative Study of Flaring Loops in Active Stars",
2006, ApJ, 164, 173
"Kinematic structure of the corona of the Ursa Major flow found using proper motions and radial velocities of single stars",
2006, A&A 451, 909
The First Extrasolar Planet Discovered with a New Generation High Throughput Doppler Instrument
2006, Astrophysical Journal, ApJ, 648, 683
"OB Stars in the Solar Neighborhood II: Kinematics",
2006, AJ, in press
"Differential Radial Velocities and Stellar Parameters of Nearby Young Stars",
2006, PASP, 118, 706
"Evidences on secular dynamical evolution of detached active binary orbits and contact binary formation",
2006, "Solar and Stellar Physics Through Eclipses", 27-29 March 2006, Side, Antalya-Turkey
"HD 203030B: an Unusually Cool Young Sub-Stellar Companion near the L/T Transition",
2006, ApJ, 651, 1166
"Search for cold debris disks around M-dwarfs",
2006, ApJ, 460, 733
"New Debris Disks Around Nearby Main Sequence Stars: Impact on The Direct Detection of Planets",
2006, ApJ, 652, 1674
"Dynamical evolution of active detached binaries on the log Jo–log M diagram and contact binary formation",
2006, MNRAS, 373, 1483
"The Hyades stream: evaporated cluster or intrusion from the inner disk?",
2007, A&A, 461, 957
"Photospheric and chromospheric activity in four young solar-type stars",
2007, ApJ, 656, 474
"NSVS01031772: A New 0.50+0.54 Msun Detached Eclipsing Binary",
2007, ApJ, in press
"Unraveling the Origins of Nearby Young Stars",
2007, ApJS, 169, 105
"Accurate masses of low mass stars GJ 765.2AB (0.83M. 0.76M.)",
2007, A&A 464, 635
"Low mass visual binaries in the solar neighbourhood: The case of HD141272",
2007, AN, 328, 521
"GJ 900: A new hierarchical system with low-mass components",
Astrophysical Bull, 62, 117
"Evidence for a Planetary Companion around a Nearby Young Star",
2007, ApJ, 660, L145
"The Gemini Deep Planet Survey - GDPS",
2007, ApJ, 670, 1367
"Habitable planets around the star Gliese 581?",
2007, A&A, 476, 1373
" An Imaging Survey for Extrasolar Planets around 54 Close, Young Stars with SDI at the VLT and MMT ",
2007, Proceedings of the conference In the Spirit of Bernard Lyot: The Direct Detection of Planets and Circumstellar Disks in the 21st Century
"An Imaging Survey for Extrasolar Planets around 45 Close, Young Stars with the Simultaneous
Differential Imager at the Very Large Telescope and MMT",
2007, ApJS, 173, 143
The effect of activity on stellar temperatures and radii
2008, A&A, 478, 507
"Constraints on Extrasolar Planet Populations from
VLT NACO/SDI and MMT SDI and Direct Adaptive Optics Imaging Surveys: Giant Planets are Rare at Large Separations",
2008, ApJ, 674, 466
"Nearby stars of the Galactic disc and halo - IV",
2008, MNRAS, 384, 173
"On the age heterogeneity of the Pleiades, Hyades and Sirius moving groups"
2008, A&A, in press
"The ages of L dwarfs"
2008, MNRAS, in press
"Coronal Structure and Abundances in Young Fast Rotators",
2008, ApJ, in press
"The exoplanet-host star iota Horologii: an evaporated member of the primordial Hyades cluster",
2008, A&A L, in press
Chromospheric activity, lithium and radial velocities
of single late-type stars possible members of young moving groups
Montes D., López-Santiago J., Fernández-Figueroa M.J., Gálvez M.C.,
ABSTRACT
Citations
"Search for substellar companions around young nearby stars",
2003, "Highlights of Spanish Astrophysics III",
Kluwer Academic Publishers,
Proceedings of the V Scientific Meeting
of the Spanish Astronomical Society (SEA)
(held in Toledo, Spain, 9-13 Septiembre 2002),
"Nearby young stars",
2003, A&A, 399, 983
"A Far Ultraviolet Spectroscopic Explorer Survey of Coronal Forbidden Lines in Late-Type Stars"
2003, ApJ, 585, 993
"A study of the Mg II 2796.34 Å emission line in late-type normal and RS CVn stars",
2003, A&A, 408, 337
"The 100 Brightest X-Ray Stars within 50 Parsecs of the Sun",
2003, AJ 126, 1996
"HD 77407 and GJ 577: two new young stellar binaries detected with the Calar Alto Adaptive Optics system ALFA",
2004, A&A, 417, 1031
"The AB Doradus Moving Group",
2004, ApJ, 613, L65
"Young stars near the Sun",
2004, ARA&A, Vol. 42, 685
"Classical T Tauri stars and substellar analogs ",
2004, A&ASS, 292, 665
"Evolution of the Solar Activity over Time and Effects on Planetary Atmospheres: I. High-energy Irradiances (1-1700 A)",
2004, ApJ, 622, 680
"Spectroscopic Confirmation of Three Suspected BY Dra Variables",
2004, IBVS, 5581, 1
"Initial Results from the Palomar Adaptive Optics Survey of Young Solar-Type Stars:
A Brown Dwarf and Three Stellar Companions ",
2004, ApJ, 617, 1330
"High-Resolution Spectroscopy of some Active Southern Stars",
2005, PASA 22, 29
"Lithium Abundances of F-, G-, and K-Type Stars: Profile-Fitting Analysis of the Li I 6708 Doublet",
2005, PASJ 57, 45
"High-Resolution Spectroscopy of Ursa Major Moving Group Stars",
2005, PASP, 117, 911
"Spots on EK Draconis - Active longitudes and cycles from long-term photometry",
2005, A&A 440, 735
The First Extrasolar Planet Discovered with a New Generation High Throughput Doppler Instrument
2006, Astrophysical Journal, ApJ, 648, 683
"Precision kinematics and related parameters of the alpha Persei open cluster",
2006, AJ 131, 2967
"Evidence for a Planetary Companion around a Nearby Young Star",
2007, ApJ, 660, L145
"Abiotic formation of O2 and O3 in high-CO2 terrestrial atmospheres",
2007, A&A, 472, 665
"Space Velocities of L- and T-Type Dwarfs",
2007, ApJ, 666, 1205
"The Chemical Composition of the Field Zero-Age Star HD 77407",
2007, ChJAA, 7, 405
"EK Draconis - Magnetic activity in the photosphere and chromosphere",
2007, A&A 472, 887
"The nearby young visual binary HIP 115147 and its common proper motion companion LSPM J2322+7847",
2007, ApJ, 668, L155
"The Gemini Deep Planet Survey - GDPS",
2007, ApJ, 670, 1367
Multiwavelength optical observations of chromospherically active binary
systems.
Gálvez M.C., Montes D., Fernández-Figueroa M.J., López-Santiago J.,
De Castro E., Cornide M.,
IV. The X-ray/EUV selected binary BK Psc (2REJ 0039+103)
ABSTRACT
Citations
"Kinematics of chromospherically active binaries and evidence of an orbital period decrease in
binary evolution",
2004, MNRAS, 349, 1069
Simultaneous Optical and X-ray Observations
of Flares and Rotational Modulation on the RS CVn Binary
HR 1099 (V711 Tau) from the MUSICOS 1998 Campaign
García-Alvarez D., Foing B., Montes D., Oliveira J., Doyle J.G.,
and MUSICOS 1998 Collaboration
ABSTRACT
Citations
"Doppler images of the RS CVn binary HR 1099 (V711 Tau) from the MUSICOS 1998 campaign",
2003, A&A 402, 1073
"Optical Photometry and X-Ray Monitoring of the ``Cool Algol'' BD +05°706:
Determination of the Physical Properties",
2003, AJ 125, 3237
"X-ray rotational modulation of a supersaturated star in IC 2391",
2003, A&A 407, 63
"Stellar magnetic activity: the solar-stellar connection",
2004, MSAIS 5, 52
"The weak-line T Tauri star V410 Tau - II. A flaring star",
2004, A&A 427, 263
"Orbital period variation in close binaries from radial velocity data and magnetic activity cycles II. HR 1099",
2004, A&A 429, 309
"Rotational brightness modulation and starspots on the RS CVn-type stars IN com, IL Com, UX Ari, and V711 Tau",
2004, ASTROPHYSICS 47 (4): 443-453
"The Coronae of AB Dor and V471 Tau: Primordial angular momentum vs tidal spin-up",
2005, ApJ, 621, 1009
"Optical and EUV observations of solar flare kernels",
2005, A&A, 444, 593,
"On the orbital period modulation of RS CVn binary systems",
2005, MNRAS, 364, 238
"Internal stellar rotation and orbital period modulation in close binary systems",
2006, MNRAS, 369, 1773
"Evidence of the FIP effect in the coronae of late-type giants",
2006, ApJ, 638, 1028
Rotational modulation of the photospheric and chrosmospheric
activity in the young, single K2-dwarf PW And
López-Santiago J., Montes D., Fernández-Figueroa M.J., Ramsey L.W.,
ABSTRACT
Citations
"Seismology and activity of the F type star HD 49933",
2005, A&A, 431, L13
"Solar-Type Activity in Main-Sequence Stars",
Springer, 2005,
(Astronomy and Astrophysics Library)
"The search for extrasolar planets: Study of line bisectors and its relation with precise radial
velocity measurements",
2006, PhD Thesis,
(Universita degli Studi di Padova)
"A Comparative Study of Flaring Loops in Active Stars",
2006, ApJ, 164, 173
The nearest young moving groups
López-Santiago J., Montes D., Crespo-Chacón I., Fernández-Figueroa M.J.,
ABSTRACT
Citations
"Search for cold debris disks around M-dwarfs",
2006, ApJ, 460, 733
"On the Time Dependence of Diferential Rotation in Young Late-type Stars",
2006, MNRAS, 373, 819
"Improved age constraints for the AB Dor quadruple system - The binary nature of AB Dor B",
2007, A&A, 462, 615
"Direct imaging of the young spectroscopic binary HD 160934",
2007, A&A, 463, 707
"Unraveling the Origins of Nearby Young Stars",
2007, ApJS, 169, 105
"New Photometry and Spectra of AB Doradus C: An Accurate Mass Determination of a Young Low-Mass Object with Theoretical Evolutionary Tracks",
2007, ApJ, 665, 736
"Low mass visual binaries in the solar neighbourhood: The case of HD141272",
2007, AN, 328, 521
"Evidence for a Planetary Companion around a Nearby Young Star",
2007, ApJ, 660, L145
"The Gemini Deep Planet Survey - GDPS",
2007, ApJ, 670, 1367
The effect of activity on stellar temperatures and radii
2008, A&A, 478, 507
"Constraints on Extrasolar Planet Populations from
VLT NACO/SDI and MMT SDI and Direct Adaptive Optics Imaging Surveys: Giant Planets are Rare at Large Separations",
2008, ApJ, 674, 466
On the kinematic evolution of young local associations and the Sco-Cen complex
2008, A&A in press
"Coronal Structure and Abundances in Young Fast Rotators",
2008, ApJ, in press
"Double-blind test program for astrometric planet detection with Gaia",
2008, A&A, in press
"Coronagraphic near-IR photometry of AB Dor C",
2008, A&A, in press
Analysis and modelling of high temporal resolution spectroscopic observations of flares on AD Leo
Crespo-Chacón I., Montes D., García-Álvarez D, Fernández-Figueroa M.J., López-Santiago J.,
Foing B.H.,
ABSTRACT
Citations
"Spectral Signatures of Photosynthesis. II. Coevolution with Other Stars And The Atmosphere on Extrasolar Worlds",
2007, AsBio, 7, 252
"Simultaneous XMM-Newton and VLT/UVES observations of the flare star CN Leonis",
2007, A&A, 468, 221
The First Extrasolar Planet Discovered with a New Generation High Throughput Doppler Instrument
[ET-1, HD 102195 b]
J. Ge, J. van Eyken, S. Mahadevan, C. DeWitt, S.R. Kane, R. Cohen, A. Vanden Heuvel,
S.W. Fleming, P. Guo, G.W. Henry, D.P. Schneider, L.W. Ramsey, R.A. Wittenmyer,
M. Endl, W.D. Cochran, E.B. Ford, E.L. Martín, G. Israelian, J. Valenti, D. Montes,
ABSTRACT
Citations
"Detection Limits from the McDonald Observatory Planet Search Program",
2006, AJ, 132, 177
"Catalog of Nearby Exoplanets",
2006, ApJ, 646, 505
"Astrophysics in 2006",
2006, PASP, in press
"Initial Results from the USNO Dispersed Fourier Transform Spectrograph",
2007, ApJ, 661, 616
"Transiting Planet Simulations from the All Sky Extrasolar Planets Survey",
2007, PASP proceedings of "Transiting Extrasolar Planets Workshop"
"A new Neptune-mass planet orbiting HD 219828",
2007, A&A, 467, 721
"Simulations for Multi-Object Spectrograph Planet Surveys",
2007, MNRAS, 377, 1610
"On constraining a transiting exoplanet's rotation rate with its transit spectrum",
2007, ApJ, in press
"An All-Sky Extrasolar Planet Survey with Multiple Object, Dispersed Fixed-delay Interferometers",
2007RMxAC..28...31G
"An All Sky Extrasolar Planet Survey with New Generation Multiple Object Doppler Instruments at Sloan Telescope",
2007RMxAC..29...30G
"New Results from the Multi-Object Keck Exoplanet Tracker",
2007RMxAC..29..151V
"Transiting Planet Simulations from the All Sky Extrasolar Planets Survey",
2007ASPC..366..303K
"Detectability of exoplanetary transits from radial velocity surveys",
22007MNRAS.380.1488K
Multiwavelength optical observations of chromospherically active binary
systems.
Gálvez M.C., Montes D., Fernández-Figueroa M.J.,
De Castro E., Cornide M.,
V. FF UMa (2RE J0933+624): a system with orbital period variation
ABSTRACT
Low-resolution spectroscopy and spectral energy distributions of selected sources towards σ Orionis
Caballero J.A., Valdivielso L., Martín E.L., Montes D., Pascual S., Pérez-González P.G.,
ABSTRACT
Methods. We acquired high-quality, low-resolution spectroscopy (R 500) of the nine targets with ALFOSC at the Nordic Optical
Telescope. We also re-analysed [24]-band photometry from MIPS/Spitzer and compiled the highest quality photometric dataset available
at the ViJHKs passbands and the four IRAC/Spitzer channels, for constructing accurate spectral energy distributions between
0.55 and 24 μm.
Results. The nine targets were classified into: one Herbig Ae/Be star with a scattering edge-on disc; two G-type stars; one X-ray
flaring, early-M, young star with chromospheric Hα emission; one very low-mass, accreting, young spectroscopic binary; two young
objects at the brown-dwarf boundary with the characteristics of classical T Tauri stars; and two emission-line galaxies, one undergoing
star formation, and another whose spectral energy distribution is dominated by an active galactic nucleus. We also discovered three
infrared sources associated with overdensities in a cold cloud of the cluster centre.
Conclusions. Low-resolution spectroscopy and spectral energy distributions are a vital tool for measuring the physical properties and
evolution of young stars and candidates in the σ Orionis cluster.
Multiwavelength optical observations of two chromospherically
active binary systems: V789 Mon and GZ Leo
Gálvez M.C., Montes D., Fernández-Figueroa M.J.,
De Castro E., Cornide M.,
ABSTRACT
Quantifying the contamination by old main-sequence stars in
young moving groups: the case of the Local Association.
López-Santiago J., Micela G., Montes D.,
ABSTRACT
Aims. Our intention is to characterize members of
the young moving groups,
determine their age distribution, and
quantify the contamination by old main-sequence
stars, in particular, for the Local Association.
Methods.
We used stars possible members of the young
(~10 - 650 Myr) moving groups from the literature.
To determine the age of the stars, we used several suitable age
indicators for young main sequence stars, i.e.,
X-ray fluxes
from the Rosat All-sky Survey database,
photometric data
from the Tycho-2, Hipparcos, and 2MASS database.
We also used spectroscopic data, in particular the equivalent width
of the lithium line Li I λ6707.8 Å and Hα,
to constrain the range of ages of the stars.
Results.
By combining photometric and spectroscopic data, we were able to
separate the young stars (10 - 650 Myr) from the old (> 1 Gyr) field ones.
We found, in particular, that the Local Association is contaminated
by old field stars at the level of ~30% .
This value must be considered as the contamination for our
particular sample, and not of the entire Local Association.
For other young
moving groups, it is more difficult to estimate the fraction of old stars
among possible members. However, the level of X-ray emission
can, at least, help to separate two age populations: stars with
< 200 Myr and stars older than this.
Conclusions.
Among the candidate members of the classical moving groups, there is a
non-negligible fraction of old field stars that should be taken into
account when studying
the stellar birthrate in the solar neighborhood. Our results are consistent
with a
scenario in which the moving groups contain both groups of young stars
formed in a recent star-formation episode and old field stars with similar
space motion. Only by combining
X-ray and optical spectroscopic data is it possible to distinguish between
these two age populations.
Chromospheric activity and rotation of FGK stars in the solar vicinity.
An estimation of the radial velocity jitter
Martínez-Arnáiz R.M., Maldonado J., Montes D., Eiroa C., Montesinos M.,
ABSTRACT
Aims. The purpose of this paper is to obtain precise chromospheric activity measurements and projected rotational velocities for
nearby (d < 25 pc) cool (spectral types F to K) stars, in order to estimate the activity-related jitter that should be expected for them.
As a complementary objective, in this paper we aim to obtain relationships between fluxes in different activity indicator lines, which
will permit a transformation of traditional activity indicators, i.e, Ca II H & K lines, to other which hold noteworthy advantages.
Methods. We used high resolution ( 50000) echelle optical spectra. Standard data reduction was performed using the IRAF ECHELLE
package. To reveal the chromospheric emission of the stars in the sample we used the spectral subtraction technique. We measured
equivalent widths of the chromospheric emission lines in the subtracted spectrum and transformed them into fluxes by applying
empirical equivalent width-flux relationships. Rotational velocities were determined using the cross-correlation technique. To infer
activity-related radial velocity (RV) jitter we used empirical relationships between this and the R'_HK index.
Results. We have measured chromospheric activity, as given by different indicators throughout the optical spectra, and projected ro-
tational velocities for 371 nearby cool stars. We have built empirical relationships among the most important chromospheric emission
lines. Finally, we have used the measured chromospheric activity to estimate the expected RV jitter for the active stars in the sample.
A high-resolution spectroscopic survey of late-type stars:
chromospheric activity, rotation, kinematics, and age.
López-Santiago J., Montes D., Gálvez-Ortiz M.C., Crespo-Chacón I., Martínez-Arnáiz R.M., Fernández-Figueroa M.J., De Castro E., Cornide M.,
ABSTRACT
Methods.
We performed spectroscopic observations with echelle spectrographs to
cover the entirety of the optical spectral range simultaneously. Standard data
reduction was performed with the IRAF echelle package. We applied the
spectral subtraction technique to reveal chromospheric emission in the stars
of the sample. The equivalent width of chromospheric emission lines was
measured in the subtracted spectra and then converted to fluxes using
equivalent width--flux relationships. Radial and rotational velocities were
determined by the cross-correlation technique. Kinematics, equivalent widths of
the lithium line λ6707.8 Å and spectral types were also determined.
Results.
A catalog of spectroscopic data is compiled: radial and rotational velocities, space motion,
equivalent widths of optical chromospheric activity indicators from
Ca II H&K to the calcium infrared triplet and the lithium line in
λ6708 Å. Fluxes in the chromospheric emission lines
and R'_HK are also determined for each observation of
star in the sample. We used these data to investigate the emission levels
of our stars. The study of the Hα emission line revealed the presence of
two different populations of chromospheric emitters in the sample, clearly
separated in the logF_Hα/F_bol - (V-J) diagram.
The dichotomy may be associated with the age of the stars.
Late-type stars members of young stellar kinematic groups.
II. Chromospherically active binaries
Montes D., Gálvez M.C., López-Santiago J., Fernández-Figueroa M.J.,
Cornide M., De Castro E.,
ABSTRACT
OTRAS PUBLICACIONES
Emisión Cromoférica Hα en sistemas binarios RS CVn
Montes D., Fernández-Figueroa M.J.,
ABSTRACT
Emisión Hα en sistema binarios
cromosféricamente activos (RS CVn y BY Dra)
Fernández-Figueroa M.J., Montes D., De Castro E.
ABSTRACT
Analysis of Chromospheric Activity Indicators in MM Her and AR Psc
Montes D., De Castro E., Cornide M., Fernández-Figueroa M.J.,
ABSTRACT
Spectroscopic study of five chromospherically active
binaries with the Hα line in emission
Montes D., De Castro E., Cornide M., Fernández-Figueroa M.J.,
ABSTRACT
Citations
"Environments of active close binaries I. ER Vulpeculae" ,
1997, A&A 318, 60
Exceso de emisión Hβ en sistemas binarios con actividad
cromosférica
Montes D., De Castro E., Cornide M.
ABSTRACT
Se ha aplicado la técnica de subtracción de un
espectro sintético obtenido con estrellas no activas del mismo tipo
espectral y clase de luminosidad que el sistema estudiado,
para poner de manifiesto
el posible llenado de la absorción Hβ por emisión cromosférica.
De esta forma se ha determinado cual es la componente del sistema binario
responsable de la emisión y se han medido la anchura equivalente (EW)
del exceso de emisión en Hβ.
En los cinco sistemas se ha encontrado un exceso de emisión Hβ
importante cuya intensidad esta fuertemente relacionada con el
comportamiento
observado en la línea Hα.
En aquellos sistemas en los que también se disponía de
observaciones en
Hα(Montes et al. 1994) se ha estudiado el cociente entre los
excesos
de emisión en ambas líneas (EW(Hα)/EW(Hβ),
el cual proporciona información (Buzasi 1993) sobre las
regiones en las que se originan estas emisiones, permitiendo determinar si la
emisión procede de regiones activas vistas sobre el disco, o si proviene
de material extenso visto sobre el limbo (protuberancias).
Flux-flux relations between excess Hα,
Ca II H & K and Hε emissions and other activity indicators in
chromospherically active binaries
Montes D., Fernández-Figueroa M.J., Cornide M., De Castro E.,
ABSTRACT
The derived excess Hα emission fluxes have been compared
with those obtained in the Ca II K and Hε lines
finding a good correlation
between these three chromospheric activity indicators.
The Hα losses seem to be more important
than Ca II K losses
for cooler stars, in fact, all the system with
Hα emission above the
continuum are cooler than 5000 K.
The Hε emission line appears to be an
alternative activity indicator.
Correlations between the excess Hα and Ca II K emissions
and other activity indicators,
(C IV in the transition region, and X-rays in the corona)
indicate that the exponents of the power-law
relations increase with the formation
temperature of the spectral features.
Excess Hβ emission in five chromospherically active binaries
Montes D., Fernández-Figueroa M.J., De Castro E., Cornide M.
ABSTRACT
First observations of Balmer Hα line in late type stars
showed that the line can appear with a core in absorption or in
emission. Lately, a filling-in of the central core of the
Hα line by chromospheric
activity has been reported in single stars
and in chromospherically active binaries
(Strassmeier et al. 1990; Fern\'andez-Figueroa et al. 1994, hereafter FFMCC;
Eker et al. 1994; Frasca & Catalano 1994; and Montes et al. 1995a, b).
For chromospherically active binary systems
a different behaviour of the Hα and Hβ
line profiles with the photometric wave has
been noted and so, several assumptions about
the emitting regions have been proposed:
emission arising from regions concentrated around starspots,
from network-like structures, or from prominence-like material
(Hall & Ramsey 1992).
We report high resolution observations of
the Balmer Hβ line in five chromospherically
active binaris (AR Psc, UX Ari, V833 Tau, KZ And, II Peg).
The component in the binary responsible for the Hβ emission
has been identified
and the excess Hβ emission equivalent width (EW) for these stars
has been determined.
When observations of these systems in the region of
the Hα line are also available (Montes et al. 1995a, b) we have used
the ratio of excess emission in Hα and Hβ as a diagnostic for
discriminating between the presence of plages and prominences in the
stellar
surface, following the results of Hall & Ramsey (1992) and Buzasi (1993)
who found that low EHα/Eβ} ($\approx$~1-2)
can be achieved both in plages and prominences viewed against the disk, but
that high ratios ($\approx$~3-15) can only be achieved in extended regions
viewed off the limb.
Citations
"Are the rotational axes perpendicular to the orbital planes in
the binary systems II. Main Sequence and Short-period RS CVn stars",
1995, Acta Astron. 45, 725
The broad components in the Hα line of very active stars: chromospheric microflaring?
Montes D., Fernández-Figueroa M.J., De Castro E., Cornide M.,
Poncet A., Sanz-Forcada J.,
ABSTRACT
Citations
"Optical and X-ray Monitoring, Doppler Imaging, and Space Motion of
the Young Star Par 1724 in Orion",
1998, A&A 334, 873
"Measurements of magnetic field strength on T Tauri stars",
1999, A&A 341, 768
"Chromospheric activity on the RS CVn-type binary UX Arietis",
2002, A&A 388, 889
"The weak-line T Tauri star V410 Tau - II. A flaring star",
2004, A&A 427, 263
Poncet A., Montes D., Fernández-Figueroa M.J., Miranda L.F.,
ABSTRACT
Citations
"C2D Spitzer-IRS spectra of disks around T Tauri stars: I. Silicate emission and grain growth",
2006, ApJ, 639, 275
"Rotation and activity of pre-main-sequence stars",
2007, ApJ, in press
Late-type stars members of young stellar kinematic groups
Montes D., Latorre A., Fernández-Figueroa M.J.
(Second "Three-Islands" Euroconference)
(May 25 - 28, 1999, Mondello, Palermo, Sicily, Italy)
R. Pallavicini, G. Micela and S. Sciortino eds.
PS_file
--
astro-ph/9906069
--
ADS Abstract
Available via WWW
Citations
"A New Association of Post-T Tauri Stars near the Sun"
2000, AJ 120,1410
Chromospherically active binaries members of young open clusters
Montes D.,
(Second "Three-Islands" Euroconference)
(May 25 - 28, 1999, Mondello, Palermo, Sicily, Italy)
R. Pallavicini, G. Micela and S. Sciortino eds.
PS_file
--
ADS Abstract
Available via WWW
Citations
"Astrometric radial velocities. III. Hipparcos measurements of nearby star clusters and associations"
2002 A&A 381, 446
Publicaciones DMG
astrax.fis.ucm.es