Comparison of the H
circumstellar disks
in Be/X-ray binaries and Be stars
R.K. Zamanov1,
P. Reig2,3,
J. Martí4,
M.J. Coe5,
J. Fabregat6,
N.A. Tomov7,
and
T. Valchev1
1
Institute of Astronomy, Bulgarian Academy of Sciences and
Isaac Newton Institute of Chile, Bulgarian Branch,
National Astronomical Observatory Rozhen,
P.O.Box 136, BG-4700 Smolyan, Bulgaria
2
Foundation for Research and Technology-Hellas,
711 10 Heraklion, Crete, Greece
3
Physics Department, University of Crete,
710 03 Heraklion, Crete, Greece
4
Departamento de Física, EPS, Universidad de
Jáen, C/ Virgen de la Cabeza, 2, E--23071 Jaén, Spain
5
Physics and Astronomy Department, Southampton University,
Southampton, S017 1BJ, UK
6
Departamento de Astronomía, Universidad de
Valencia, E--46100 Burjassot, Valencia, Spain
7
National Astronomical Observatory Rozhen,
P.O.Box 136, BG-4700 Smolyan, Bulgaria
We present a comparative study of the circumstellar disks in Be/X-ray
binaries and isolated Be stars based upon the
H emission line.
From this comparison it follows that the overall structure of the
disks in the Be/X-ray binaries is similar to the disks of other Be
stars, i.e. they are axisymmetric and rotationally supported. The
factors for the line broadening (rotation and temperature) in the
disks of the Be stars and the Be/X-ray binaries seem to be identical.
However, we do detect some intriguing differences between the
envelopes. On average, the circumstellar disks of the Be/X-ray
binaries are twice as dense as the disks of the isolated Be stars.
The different distribution of the Be/X-ray binaries and the Be stars
seen in the full width half maximum versus peak separation diagram
indicates that the disks in Be/X-ray binaries have on average a
smaller size, probably truncated by the compact object.
Accepted by Astronomy and Astrophysics
Preprints on the web at
http://arXiv.org/abs/astro-ph/0012371
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