Issue |
A&A
Volume 400, Number 1, March II 2003
|
|
---|---|---|
Page(s) | 271 - 277 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361:20021883 | |
Published online | 24 February 2003 |
The rotational velocity of the sdOB primary of the eclipsing binary system LB 3459 (AA Dor) *,**
1
Dr.-Remeis-Sternwarte, Sternwartstraße 7, 96049 Bamberg, Germany
2
Institut für Astronomie und Astrophysik, Abteilung Astronomie, Sand 1, 72076 Tübingen, Germany
Corresponding author: T. Rauch, rauch@astro.uni-tuebingen.de
Received:
8
November
2002
Accepted:
17
December
2002
We present an analysis of the rotational velocity of the primary of LB 3459 based on 107 new
high-resolution and high- ESO VLT UVES spectra. 105 of them cover a complete orbital period
(0.26 d) of this binary system.
We have determined
an orbital period of
,
a radial velocity amplitude of
, and
.
From simulations of the He II
λ 4686 Å line profile (based on NLTE model atmosphere
calculations), we derive
.
We present an animation which shows the orbital movement of the binary system,
its synthetic lightcurve,
and compares the phase-dependent variation of the predicted with the
observed He II
λ 4686 Å line profile.
The radius of the cool component is almost the same size like Jupiter but its mass is about 70 times higher
than Jupiter's mass. Thus, from its present mass (
),
the secondary of LB 3459
lies formally within the brown-dwarf mass range (
).
It might be a former planet which has survived the previous common-envelope
phase and even has gained mass.
Key words: stars: binaries: eclipsing / stars: fundamental parameters / stars: individual: LB 3459 / stars: individual: AA Dor / stars: low-mass, brown dwarfs / stars: rotation
© ESO, 2003
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