Properties and nature of Be stars XX. Binary nature and orbital elements of gamma Cas

Citation
P. Harmanec et al., Properties and nature of Be stars XX. Binary nature and orbital elements of gamma Cas, ASTRON ASTR, 364(2), 2000, pp. L85-L88
Citations number
26
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Space Sciences
Journal title
ASTRONOMY AND ASTROPHYSICS
ISSN journal
0004-6361 → ACNP
Volume
364
Issue
2
Year of publication
2000
Pages
L85 - L88
Database
ISI
SICI code
0004-6361(200012)364:2<L85:PANOBS>2.0.ZU;2-2
Abstract
An analysis of accurate radial Velocities (RVs) of the Be star gamma Cas fr om 295 Reticon spectrograms secured between October 1993 and May 2000 allow ed us to prewhiten the RVs for the long-term changes and to obtain the firs t orbital RV curve of this star. The orbital period is 203(d).59 and the or bit has an eccentricity of 0.26. The orbital motion is detectable even in t he published velocities, based on photographic spectra. This implies that g amma Cas is a primary component of a spectroscopic binary. The secondary ha s a mass of about 1 M., appropriate for a white dwarf or a neutron star, bu t it could also be a normal late-type dwarf. The ultimate solution of the d ispute whether the observed X-ray emission is associated with the secondary or with the primary will need further dedicated studies.