On the Mass Limit of the X-ray Source in Cygnus X-1
Abstract
Summary. Limiting values for the mass of the X-ray emitting source in Cygnus X- I are derived without an initial assumption on the mass of the primary of HDE 226868. It is shown that the model of Trimble et al. (1973) with a low mass, low surface gravity B 0 1 star is in contradiction to the observations. The heating effect on the facing hemisphere of the OB star by the X-rays of the secondary is shown to be negligible in accordance to the observations. The mass function and the Roche geometry set lower and upper limits, respectively, on the mass of the secondary. According to these restrictions the mass of the X-ray source most probably is 6.0 < <=7.3, thus giving evidence for the existence of a black hole in Cygnus X- I. Key words: X-ray binaries - black hole
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- November 1973
- Bibcode:
- 1973A&A....28..473M