New Gamma Cas-like objects: X-ray and optical observations of SAO49725 and HD161103
arXiv:astro-ph/0603098 · doi:10.1051/0004-6361:20054589
Abstract
A growing number of early Be stars exhibit unusually hard X-ray spectra and luminosities intermediate between those typical of early type stars and those emitted by most Be/X-ray binaries in quiescence. We report on XMM-Newton and optical observations of two such Be stars, SAO 49725 and HD 161103. The nature of the hard-thermal X-ray emission is discussed in the light of the models proposed for Gamma Cas, magnetic disc-star interaction or accretion onto a compact companion object - neutron star or white dwarf. These two new objects added to similar cases discovered in XMM-Newton surveys point at the emergence of a new class of Gamma Cas analogs.
14 pages, 9 figs, accepted for publication in A&A
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