Astron. Astrophys. Suppl. Ser. 146, 103-140
Multiwavelength optical observations of chromospherically
active binary systems
III. High resolution echelle spectra from
Ca II H & K to Ca II IRT
D. Montes1,2 - M.J. Fernández-Figueroa1 - E. De Castro1 - M. Cornide1 - A. Latorre1 - J. Sanz-Forcada1,3
Send offprint request: D. Montes
Correspondence to: e-mail: email@example.com
Departamento de Astrofísica,
Facultad de Ciencias Físicas,
Universidad Complutense de Madrid, E-28040 Madrid, Spain
2 - Guest observer at McDonald Observatory, Texas, U.S.A.
3 - Harvard-Smithsonian Center for Astrophysics,
60 Garden St., Cambridge, MA 02138, U.S.A.
Received April 10; accepted July 3, 2000
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
High resolution echelle spectra
including all the optical chromospheric activity indicators
from the Ca II
H & K to Ca II
are analysed here for 16 systems.
The chromospheric contribution in these lines has been determined
using the spectral subtraction technique.
Very broad wings have been found in the subtracted H
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 H
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.
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
line has been detected
as an absorption feature in mainly all the giants of the sample.
Total filling-in of the He I
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
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.
Key words: stars: activity
-- stars: binaries: close
-- stars: binaries: spectroscopic
-- stars: chromospheres
-- stars: late-type
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