Evidence for Sub-Chandrasekhar Type Ia Supernovae from Stellar Abundances in Dwarf Galaxies
Evidence for Sub-Chandrasekhar Type Ia Supernovae from Stellar Abundances in Dwarf Galaxies
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DOI：
10.3847/1538-4357/ab2c02
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发表时间：
2019-06
期刊：
影响因子：
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通讯作者：
E. Kirby;Justin L. Xie;Rachel Guo;Mithi A. C. de los Reyes;M. Bergemann;M. Kovalev;K. Shen;A. Piro
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文献类型：
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作者：
E. Kirby;Justin L. Xie;Rachel Guo;Mithi A. C. de los Reyes;M. Bergemann;M. Kovalev;K. Shen;A. Piro
尽管Ia型超新星（SNe Ia）在宇宙学和化学演化中具有重要意义，但对于它们的祖先还没有达成共识。我们解决这个问题，使用我们以前发表的目录中的镁，硅，钙，铬，铁，钴，镍丰度的矮星系卫星的银河系（MW），以约束质量的白色矮星（WD）在一个典型的超新星Ia爆炸。我们拟合了一个简单的双线性模型来描述[X/Fe]与[Fe/H]的演化，其中X代表上述每个元素。我们使用的演变[Mg/Fe]加上理论超新星产量隔离什么分数的元素起源于超新星Ia。然后，我们推断出除了Mg之外的所有元素的SNe Ia的[X/Fe]产额。我们比较这些观测推断收益率最近的理论预测两个类的克拉塞卡质量（MCh）超新星Ia以及亚MCh超新星Ia。大多数推断的超新星Ia产额与所有的理论模型一致，但[Ni/Fe]仅与亚MCh模型一致。我们的结论是，在古代矮星系的超新星Ia的主导类型是一个亚MCh WD的爆炸。具有较长星星形成历史的MW星系和矮星系具有较高的[Ni/Fe]丰度，这可能表明，对于星星形成持续至少几个Gyr的星系，Ia型超新星的主导类是不同的。
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 (MCh) SN Ia as well as sub-MCh 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-MCh models. We conclude that the dominant type of SN Ia in ancient dwarf galaxies is the explosion of a sub-MCh 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.