Double-Degenerate Carbon-Oxygen and Oxygen-Neon White Dwarf Mergers: A New Mechanism for Faint and Rapid Type Ia Supernovae
Kashyap, R; Haque, T; Lorén-Aguilar, P; et al.García-Berro, E; Fisher, RT
Date: 19 December 2018
Journal
Astrophysical Journal
Publisher
American Astronomical Society
Publisher DOI
Abstract
Type Ia supernovae (SNe Ia) originate from the thermonuclear explosion of carbon-oxygen white
dwarfs (CO WDs), giving rise to luminous optical transients. A relatively common variety of subluminous
SNe Ia events, referred to as SNe Iax, are believed to arise from the failed detonation of a
CO WD. In this paper, we explore failed ...
Type Ia supernovae (SNe Ia) originate from the thermonuclear explosion of carbon-oxygen white
dwarfs (CO WDs), giving rise to luminous optical transients. A relatively common variety of subluminous
SNe Ia events, referred to as SNe Iax, are believed to arise from the failed detonation of a
CO WD. In this paper, we explore failed detonation SNe Ia in the context of the double-degenerate
channel of merging white dwarfs. In particular, we have carried out the first fully three-dimensional
simulation of the merger of a ONe WD with a CO WD. While the hot, tidally-disrupted carbon-rich
disk material originating from the CO WD secondary is readily susceptible to detonation in such a
merger, the ONe WD primary core is not. This merger yields a failed detonation, resulting in the ejection
of a small amount of mass, and leaving behind a kicked, super-Chandrasekhar ONe WD remnant
enriched by the fallback of the products of nuclear burning. The resulting outburst is a rapidly-fading
optical transient with a small amount of radioactive 56Ni powering the light curve. Consequently, the
ONe-CO WD merger naturally produces a very faint and rapidly-fading transient, fainter even than
the faintest Type Iax events observed to date, such as SN 2008ha and SN 2010ae. More massive ONe
primaries than considered here may produce brighter and longer-duration transients.
Physics and Astronomy
Faculty of Environment, Science and Economy
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