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Double-Degenerate Carbon-Oxygen and Oxygen-Neon White Dwarf Mergers: A New Mechanism for Faint and Rapid Type Ia Supernovae

Authors :
Kashyap, Rahul
Haque, Tazkera
Lorén-Aguilar, Pablo
García-Berro, Enrique
Fisher, Robert T.
Publication Year :
2018

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 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 $^{56}$Ni 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 $2008$ha and SN 2010ae. More massive ONe primaries than considered here may produce brighter and longer-duration transients.<br />Comment: 13 pages, 8 figures, accepted to The Astrophysical Journal. Dedicated to the memory of our late colleague Enrique Garc\'ia-Berro

Details

Database :
arXiv
Publication Type :
Report
Accession number :
edsarx.1811.00013
Document Type :
Working Paper
Full Text :
https://doi.org/10.3847/1538-4357/aaedb7