Optical properties of binary X-ray sources.
Abstract
The optical counterparts of six X-ray sources known to be in binary systems are discussed (HZ Her/Her X-1, ?/Cen X-3, HD 153919/3U 1700-37, HD 77581/Vela XR-1, Sk 160/SMC X-1, and HDE 226868/Cyg X-1). Detailed summaries of data for each system are presented and include X-ray and optical properties, establishment of optical identifications, and mass estimates. Significant facts noted include the unusual spectral type, optical luminosity and variations, and position of HZ Her; the difficulty in determining the counterpart of Cen X-3; and the substantial evidence that Cyg X-1 is a black hole. Attempts to locate an optical counterpart to Cyg X-3 are described, and uncertainties in determining the masses of X-ray sources with and without regular pulsations are noted.
- Publication:
-
Astrophysics and Gravitation
- Pub Date:
- 1974
- Bibcode:
- 1974asgr.proc...73B
- Keywords:
-
- Binary Stars;
- Optical Properties;
- X Ray Astronomy;
- X Ray Stars;
- Black Holes (Astronomy);
- Neutron Stars;
- Pulsars;
- Stellar Evolution;
- Stellar Radiation;
- Ubv Spectra;
- Astrophysics