Reconciling 56Ni production in Type Ia supernovae with double degenerate scenarios. Issue 4 (14th January 2014)

• Record Type: Journal Article
• Authors: Piro, Anthony L.; Thompson, Todd A.; Kochanek, Christopher S.
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 438:Issue 4(2014)
• Page Start: 3456
• Page End: 3464
• Publication Date: 2014-01-14
• Subjects: nuclear reactions, nucleosynthesis, abundances -- supernovae: general -- white dwarfs; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stt2451
• Languages: English
• ISSNs: 0035-8711

Abstract

Abstract: We combine the observed distribution of Type Ia supernova (SN Ia) 56 Ni yields with the results of sub-Chandrasekhar detonation and direct collision calculations to estimate what mass white dwarfs (WDs) should be exploding for each scenario. For collisions, the average exploding WD mass must be peaked at ≈0.75 M⊙, significantly higher than the average field WD mass of ≈0.55–0.60 M⊙ . Thus, if collisions produce most SNe Ia, then a mechanism must exist that favours higher mass WDs. On the other hand, in old stellar populations, collisions would naturally result in low-luminosity SNe Ia, and we suggest these may be related to 1991bg-like events. For sub-Chandrasekhar detonations, the average exploding WD mass must be peaked at ≈1.1 M⊙ . This is similar to the average total mass in WD–WD binaries, but it is not clear whether double degenerate mergers would synthesize sufficient 56 Ni to match observed yields. If not, then actual ≈1.1 M⊙ WDs would be needed for sub-Chandrasekhar detonations. Since such high-mass WDs are produced relatively quickly in comparison to the age of SN Ia environments, this would require either accretion on to lower mass WDs prior to ignition or a long time-scale between formation of the ≈1.1 M⊙ WD and ignition.