Issue |
A&A
Volume 369, Number 3, April III 2001
|
|
---|---|---|
Page(s) | 908 - 914 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361:20010168 | |
Published online | 15 April 2001 |
Contribution to the search of binaries among Am stars*
II. HD 81976 and HD 98880, double-lined spectroscopic binaries
UMR 5572 d'Astrophysique, Observatoire Midi-Pyrénées -Centre National de la Recherche Scientifique, 14 avenue Édouard Belin, 31400 Toulouse, France
Corresponding author: J.-M. Carquillat, jean-michel.carquillat@obs-mip.fr
Received:
22
November
2000
Accepted:
15
January
2001
We present the results of the observations of two Am stars of eighth magnitude,
the double-lined spectroscopic binaries HD 81976 and HD 98880, carried out with
the CORAVEL instrument at the Observatoire de Haute-Provence in order to determine
their orbital elements. We found 1) for HD 81976: days,
HJD,
,
,
km s-1,
km s-1,
km s-1,
Gm,
Gm,
,
,
and 2) for HD 98880:
days,
HJD (ascending node),
,
km s-1,
km s-1,
km s-1,
Gm,
Gm,
,
.
The first of these two systems, HD 81976, is formed by two quasi-identical stars,
and the Hipparcos data (MV,
) are consistent with late A stars in effective
temperature; it is likely that the components rotate synchronised with the orbital
motion. A third body may be present in this system since (i) the orbit has
a significant eccentricity despite its short period and (ii) the systemic velocity
V0 shows a possible drift.
For the second system, HD 98880, we give
and we propose a simple model based upon
Strömgren photometric indices and the HR theoretical
diagram of Schaller et al (1992) in addition to orbital parameters
and Hipparcos data:
K,
,
,
,
.
The components do not rotate synchronously contrary to HD 81976.
Both binaries appear to be detached systems without possibility of eclipses.
Key words: stars: individual: HD 81976, HD 98880 / binaries: spectroscopic / stars: fundamental parameters
© ESO, 2001
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