Evidence for Sub-Chandrasekhar Type Ia Supernovae from Stellar Abundances in Dwarf Galaxies

There is no consensus on the progenitors of Type Ia supernovae (SNe Ia) despite their importance for cosmology and chemical evolution. We address this question using our previously published catalogs of Mg, Si, Ca, Cr, Fe, Co, and Ni abundances in dwarf galaxy satellites of the Milky Way (MW) to con...

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Bibliographic Details
Published in:The Astrophysical journal 2019-08, Vol.881 (1), p.45
Main Authors: Kirby, Evan N., Xie, Justin L., Guo, Rachel, de los Reyes, Mithi A. C., Bergemann, Maria, Kovalev, Mikhail, Shen, Ken J., Piro, Anthony L., McWilliam, Andrew
Format: Article
Language:English
Subjects:
Abundance
Astrophysics
Chemical evolution
Chromium
Cosmology
Dwarf galaxies
Galactic evolution
Galaxies
Iron
Magnesium
Milky Way
Nickel
Organic chemistry
Progenitors (astrophysics)
Silicon
Star & galaxy formation
Star formation
Stars & galaxies
Stellar evolution
Supernova
Supernovae
White dwarf stars
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Summary:There is no consensus on the progenitors of Type Ia supernovae (SNe Ia) despite their importance for cosmology and chemical evolution. We address this question using our previously published catalogs of Mg, Si, Ca, Cr, Fe, Co, and Ni abundances in dwarf galaxy satellites of the Milky Way (MW) to constrain the mass at which the white dwarf (WD) explodes during a typical SN Ia. We fit a simple bi-linear model to the evolution of [X/Fe] with [Fe/H], where X represents each of the elements mentioned above. We use the evolution of [Mg/Fe] coupled with theoretical supernova yields to isolate what fraction of the elements originated in SNe Ia. Then, we infer the [X/Fe] yield of SNe Ia for all of the elements except Mg. We compare these observationally inferred yields to recent theoretical predictions for two classes of Chandrasekhar-mass ( M Ch ) SN Ia as well as sub- M Ch SNe Ia. Most of the inferred SN Ia yields are consistent with all of the theoretical models, but [Ni/Fe] is consistent only with sub- M Ch models. We conclude that the dominant type of SN Ia in ancient dwarf galaxies is the explosion of a sub- M Ch WD. The MW and dwarf galaxies with extended star formation histories have higher [Ni/Fe] abundances, which could indicate that the dominant class of SN Ia is different for galaxies where star formation lasted for at least several Gyr.
ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/ab2c02