Triggering micronovae through magnetically confined accretion flows in accreting white dwarfs
Abstract
Rapid bursts at optical wavelengths have been reported for several accreting white dwarfs. In these bursts, the optical luminosity can increase by up to a factor of 30 in less than an hour, before fading on time-scales of several hours, and the energy release can reach ~1039 erg ('micronovae'). Several systems have also shown these bursts to be semirecurrent on time-scales of days to months, and the temporal profiles of these bursts strongly resemble those observed in Type-I X-ray bursts in accreting neutron stars. It has been suggested that the observed micronovae may be the result of localized thermonuclear runaways in the surface layers of accreting white dwarfs. Here we propose a model in which the magnetic confinement of accretion streams on to the accreting magnetic white dwarf may trigger localized thermonuclear runaways. The model proposed to trigger micronovae appears to favour magnetic systems with both a high white dwarf mass and a high mass-transfer rate.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- July 2022
- DOI:
- 10.1093/mnrasl/slac042
- arXiv:
- arXiv:2204.09073
- Bibcode:
- 2022MNRAS.514L..11S
- Keywords:
-
- magnetic fields;
- stars: novae;
- cataclysmic variables;
- transients: novae;
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 4 pages, 1 figure. Accepted 2022 April 12 in MNRAS. Received 2022 April 8