On X-Ray Luminosities of the Quiescent X-Ray Novae: GS 2000+25 and GS 2023+338
Abstract
We present the results of X-ray scan observations of X-ray novae during quiescence, performed with the Large-Area Proportional Counters (LAC) onboard Ginga. The scans of GS 2000+25 were made 155d before the peak of the 1988 outburst and 382d after the peak. The derived upper limits to the X-ray luminosity in the energy range between 1.2 and 37.1 keV are (3--9)times 10(33) erg s(-1) for a distance of D ~ 2 kpc. For such X-ray luminosities, the mass-overflow instability of the companion star is difficult to trigger. GS 2023+338 was X-ray scanned 320d before the peak of the 1989 outburst and 442-443d after the peak. LAC found an X-ray source at a distance of ~ 0.1 arc degree from the position of GS 2023+338 after the eruption. The possibility that this source is GS 2023+338, itself, cannot be discarded if its luminosity is highly variable. If this is the case, the quiescent X-ray luminosity of GS 2023+338 is of order 10(34) erg s(-1) for a distance of D ~ 3 kpc, and may be sufficient to trigger a mass-overflow instability. The disk instability model is, on the other hand, viable for both stars.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- April 1992
- Bibcode:
- 1992PASJ...44..117M
- Keywords:
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- Accretion Disks;
- Novae;
- Stellar Luminosity;
- Variable Stars;
- X Ray Binaries;
- Ginga Satellite;
- Light Curve;
- Proportional Counters;
- Stellar Mass;
- Stellar Models;
- Astrophysics;
- ACCRETION DISKS;
- INSTABILITY;
- X-RAY NOVAE