10 Micron Detection of the Hard X-Ray Transient GRO J0422+32: Free-Free Emission from an X-Ray--driven Accretion Disk Wind?
Abstract
We report the detection of 10 micrometer emission from the transient low-mass X-ray binary (LMXB) and optical nova GRO J0422+32 near the maximum of its outburst. We discuss this result in terms of (1) a 'standard' model according to which low-energy radiation of LMXB is caused by reprocessing of X-rays in an accretion disk; (2) emission from a cool secondary star; (3) emission from dust grains heated by the transient X-rays, and (4) free-free emission from an X-ray-driven wind from the accretion disk. Only the fourth alternative provides a viable explanation for the observed 10 micrometer emission, with a mass-loss rate in the disk wind that may be substantially higher than the rate of accretion onto the compact star. The presence of such a wind may have a profound effect on the evolution of the binary, and contribute to the solution of the 'birthrate problem' of millisecond ratio pulsars.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 1994
- DOI:
- 10.1086/187403
- Bibcode:
- 1994ApJ...429L..19V
- Keywords:
-
- Accretion Disks;
- Stellar Mass Accretion;
- Stellar Winds;
- X Ray Binaries;
- Astrophysics;
- ACCRETION;
- ACCRETION DISKS;
- STARS: BINARIES: CLOSE;
- STARS: INDIVIDUAL ALPHANUMERIC: GRO J0422;
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