The standstill luminosity in Z Cam systems
Abstract
We consider accretion discs in close binary systems. We show that the heating of a disc at the impact point of the accretion stream contributes significantly to the local energy budget at its outer edge. As a result, the thermal balance relation between local accretion rate and surface density (the `S-curve') changes; the critical mass transfer rate above which no dwarf nova outbursts occur can be up to 40 per cent smaller than without impact heating. Standstills in Z Cam systems thus occur at smaller mass transfer rates than otherwise expected, and are fainter than the peak luminosity during the dwarf nova phase as a result.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- May 2001
- DOI:
- 10.1046/j.1365-8711.2001.04223.x
- arXiv:
- arXiv:astro-ph/0012379
- Bibcode:
- 2001MNRAS.323..584S
- Keywords:
-
- ACCRETION;
- ACCRETION DISCS;
- INSTABILITIES;
- BINARIES: CLOSE;
- NOVAE;
- CATACLYSMIC VARIABLES;
- Astrophysics
- E-Print:
- 3 pages, 3 figures. Accepted for publication in MNRAS