Upper limits to X-ray emission from nova Vulpeculae 1976
Abstract
Two recent optical novae have been observed to radiate a substantial flux of medium energy X rays (nova Monocerotis1, and A1524-61 (ref. 2)), the X-ray luminosity in both cases reached a maximum at the same time as the optical luminosity and was over 100 times greater. In contrast, an unsuccessful search was made by Hoffman et al.3 for X-ray emission from nova Cygni 1975 and the ratio of X-ray to optical luminosity in that case was found to be less than 10-4. Brecher and Morrison4 have suggested that the tyrge differences in this ratio might be related to the rate of mass exchange in the binary system, believing that the X-ray emission arises from the shock heating of dense circumstellar material by the nova ejecta. Only systems with a high density in the accretion flow, such as recurrent novae, will therefore generate large X-ray luminosities.
- Publication:
-
Nature
- Pub Date:
- June 1977
- DOI:
- 10.1038/267685a0
- Bibcode:
- 1977Natur.267..685C
- Keywords:
-
- Novae;
- Radiant Flux Density;
- Stellar Radiation;
- X Ray Astronomy;
- Periodic Variations;
- Range (Extremes);
- Stellar Luminosity;
- Astrophysics