Properties and nature of Be stars 28. Implications of systematic observations for the nature of the multiple system with the Be star o Cassiwopeae and its circumstellar environment

0354785 - ASÚ 2011 RIV FR eng J - Journal Article
Koubský, Pavel - Hummmel, C.A. - Harmanec, P. - Tycner, C. - van Leeuwen, F. - Yang, S. - Šlechta, Miroslav - Božić, H. - Zavala, R.T. - Ruzdjak, D. - Sudar, D.
Properties and nature of Be stars 28. Implications of systematic observations for the nature of the multiple system with the Be star o Cassiwopeae and its circumstellar environment.
Astronomy & Astrophysics. Roč. 517, July (2010), A24/1-A24/29. ISSN 0004-6361. E-ISSN 1432-0746
R&D Projects: GA ČR GA205/03/0788; GA ČR GD205/08/H005
Grant - others:GA ČR(CZ) GA205/06/0304; GA ČR(CZ) GAP209/10/0715; ESA(XE) ESA-PECS project No. 98058
Institutional research plan: CEZ:AV0Z10030501
Keywords : close binaries * spectroscopic
Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics
Impact factor: 4.410, year: 2010

The analysis of radial velocities of the Be star o Cas from spectra taken between 1992 and 2008 at the Ondřejov Observatory and the Dominion Astrophysical Observatory allowed us to reconfirm the binary nature of this object, first suggested by Abt and Levy in 1978, but later refuted by several authors. The orbital parameters of this SB1 system imply a very high mass function of about one solar mass. This in turn leads to a very high mass of the secondary, possibly higher than that of the primary. In order to look for such a massive secondary, o Cas was observed with the Navy Prototype Optical Interferometer, which allowed the binary components to be spatially resolved for the first time. The interferometric observations lead to the detection of a secondary, about 3 mag fainter than the primary. The possible properties of this peculiar binary system and the reasons why the massive secondary does not dominate the optical spectrum are discussed.
Permanent Link: http://hdl.handle.net/11104/0193705