Triggering micronovae through magnetically confined accretion flows in accreting white dwarfs

Scaringi, S; Groot, PJ; Knigge, C; Lasota, J-P; de Martino, D; Cavecchi, Y; Buckley, DAH; Camisassa, ME

Abstract

Rapid bursts at optical wavelengths have been reported for several accreting white dwarfs, where the optical luminosity can increase by up to a factor 30 in less than an hour fading on timescales of several hours, and where the energy release can reach ≈1039 erg (“micronovae”). Several systems have also shown these bursts to be semi-recurrent on timescales 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 localised thermonuclear runaways on the surface layers of accreting white dwarfs. Here we propose a model where magnetic confinement of the accretion stream on to accreting magnetic white dwarfs may trigger localised thermonuclear runaways. The proposed model to trigger micronovae appears to favour magnetic systems with both high white dwarf masses and high mass-transfer rates.

Citation

Scaringi, S., Groot, P., Knigge, C., Lasota, J.-P., de Martino, D., Cavecchi, Y., Buckley, D., & Camisassa, M. (2022). Triggering micronovae through magnetically confined accretion flows in accreting white dwarfs. Monthly Notices of the Royal Astronomical Society: Letters, 514(1), L11-L15. https://doi.org/10.1093/mnrasl/slac042

• Journal Article Type: Article
• Acceptance Date: Apr 12, 2022
• Online Publication Date: Apr 20, 2022
• Publication Date: 2022-07
• Deposit Date: Apr 28, 2022
• Publicly Available Date: Apr 29, 2022
• Journal: Monthly notices of the Royal Astronomical Society: Letters
• Electronic ISSN: 1745-3933
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 514
• Issue: 1
• Pages: L11-L15
• DOI: https://doi.org/10.1093/mnrasl/slac042
• Public URL: https://durham-repository.worktribe.com/output/1209632
• Related Public URLs: https://arxiv.org/abs/2204.09073