Evidence for Sub-Chandrasekhar Type Ia Supernovae from Stellar Abundances in Dwarf Galaxies
Abstract
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.
Additional Information
© 2019 The American Astronomical Society. Received 2019 April 26; revised 2019 June 18; accepted 2019 June 22; published 2019 August 12. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. We thank Marten van Kerkwijk, Julianne Dalcanton, Ivo Seitenzahl, Robert Fisher, Ken'ichi Nomoto, Mansi Kasliwal, Alex Ji, and Norbert Werner for insightful conversations. We also thank the anonymous referee for a helpful report. This material is based upon work supported by the National Science Foundation under grant No. AST-1614081. E.N.K. gratefully acknowledges support from a Cottrell Scholar award administered by the Research Corporation for Science Advancement as well as funding from generous donors to the California Institute of Technology. We are grateful to the many people who have worked to make the Keck Telescope and its instruments a reality and to operate and maintain the Keck Observatory. The authors wish to extend special thanks to those of Hawaiian ancestry on whose sacred mountain we are privileged to be guests. Without their generous hospitality, none of the observations presented herein would have been possible. We express our deep gratitude to the staff at academic and telescope facilities whose labor maintains spaces for scientific inquiry. Facility: Keck:II (DEIMOS). - Software: MOOG (Sneden 1973; Sneden et al. 2012).Attached Files
Published - Kirby_2019_ApJ_881_45.pdf
Accepted Version - 1906.10126.pdf
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Additional details
- Eprint ID
- 97706
- Resolver ID
- CaltechAUTHORS:20190807-125436624
- W. M. Keck Foundation
- AST-1614081
- NSF
- Cottrell Scholar of Research Corporation
- Caltech
- Created
-
2019-08-07Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field
- Caltech groups
- Astronomy Department