CAOSP abstracts, Volume: 27, No.: 3, year: 1998
- Author(s): NORTH, P.; GINESTET, N.; CARQUILLAT, J.-M.; CARRIER, F.; UDRY, S.
- Journal: Contributions of the Astronomical Observatory Skalnate Pleso,
vol. 27, no. 3, p. 179-183.
- Date: 04/1998
- Title: Binaries among Ap and Am stars
- Keyword(s): STARS: BINARIES: SPECTROSCOPIC, STARS: CHEMICALLY PECULIAR,
STARS: EVOLUTION
- Pages: 179 -- 183
Abstract:
The results of long-term surveys of radial velocities of cool Ap and Am
stars are presented. There are two samples, one of about 100 Ap stars
and the other of 86 Am stars. Both have been observed with the CORAVEL
scanner from Observatoire de Haute-Provence (CNRS), France.
The conspicuous lack of short-period binaries among cool Ap stars seems
confirmed, although this may be the result of an observational bias;
one system has a period as short as 1.6 days. A dozen new orbits could be
determined, including that of one SB2 system. Considering the mass functions
of 68 binaries from the literature and from our work, we conclude that
the distribution of the mass ratios is the same for the Bp-Ap stars than
for normal G dwarfs. Among the Am stars, we found 52 binaries, i.e. 60%;
an orbit could be computed for 29 of them. Among these 29, there are 7 SB2
systems, one triple and one quadruple system. The 21 stars with an apparently
constant radial velocity may show up later as long-period binaries with
a high eccentricity. The mass functions of the SB1 systems are compatible
with cool main-sequence companions, also suggested by ongoing spectral
observations.
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