The chemical signature of SNIax in the stars of Ursa minor?
Abstract
Recently, a new class of supernovae Ia was discovered: the supernovae Iax. The increasing sample of these objects share common features as lower maximum-light velocities and typically lower peak magnitudes. In our scenario, the progenitors of the SNe Iax are very massive white dwarfs, possibly hybrid C+O+Ne white dwarfs; due to the accretion from a binary companion, they reach the Chandrasekhar mass and undergo a central carbon deflagration, but the deflagration is quenched when it reaches the outer O +Ne layer. This class of SNe Ia are expected to be rarer than standard SNe Ia and do not affect the chemical evolution in the solar neighbourhood; however, they have a short delay time and they could influence the evolution of metal-poor systems. Therefore, we have included in a stochastic chemical evolution model for the dwarf spheroidal galaxy Ursa minor the contribution of SNe Iax. The model predicts a spread in [Mn/Fe] in the ISM medium at low metallicity and - at the same time - a decrease of the [alpha/Fe] elements, as in the classical time delay model. This is in surprising agreement with the observed abundances in stars of Ursa minor and provide a strong indication to the origin of this new classes of SNIa.
- Publication:
-
Memorie della Societa Astronomica Italiana
- Pub Date:
- 2017
- DOI:
- 10.48550/arXiv.1708.00685
- arXiv:
- arXiv:1708.00685
- Bibcode:
- 2017MmSAI..88..412C
- Keywords:
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- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Proceedings of the conference "The AGB-Supernovae Mass Transition", held at Rome Observatory, March 27-31, 2017