Hard X-rays from the contact binary VW Cephei.
Abstract
Ginga observations of the contact binary VW Cep are presented. The observed X-ray luminosity is 1.1 x 10 exp 30 erg/s in the energy range of 2-10 keV, assuming a distance of 31 pc. No evidence for X-ray orbital modulation or for flare events was detected. The observed X-ray spectrum is very hard, and can be represented well either by a thermal bremsstrahlung model with a temperature of 11.2 +40/-2.3 keV or a power-law model with a photon index of 1.90 +0.24/-0.20. These observational results are interpreted in terms of the thermal emission from a hot coronal plasma extending beyond the stellar size. The observed upper limit on the iron K-line intensity is considerably lower than the theoretical prediction.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- March 1992
- DOI:
- 10.1093/mnras/255.2.192
- Bibcode:
- 1992MNRAS.255..192T
- Keywords:
-
- Binary Stars;
- Light Curve;
- X Ray Sources;
- Exosat Satellite;
- Proportional Counters;
- Spaceborne Astronomy;
- Stellar Models;
- Stellar Spectra;
- Astrophysics