The birth rate of SNe Ia from hybrid CONe white dwarfs

TL;DR

This paper explores how hybrid CONe white dwarfs, formed under uncertain nuclear burning conditions, can significantly contribute to the population of Type Ia supernovae, especially the peculiar 2002cx-like subclass.

Contribution

It introduces the role of hybrid CONe white dwarfs in SN Ia progenitors and quantifies their potential contribution to the overall SN Ia rate.

Findings

Hybrid CONe WDs can reach the Chandrasekhar limit with minimal accretion.

SNe Ia from hybrid WDs are typically young, with delays of 0.1 to 1 Gyr.

Hybrid WDs may account for several percent of all SNe Ia, including some peculiar types.

Abstract

Considering the uncertainties of the C-burning rate (CBR) and the treatment of convective boundaries, Chen et al. (2014) found that there is a regime where it is possible to form hybrid CONe white dwarfs (WDs), i.e. ONe WDs with carbon-rich cores. As these hybrid WDs can be as massive as 1.30 $M_{\odot}$, not much mass needs to be accreted for these objects to reach the Chandrasekhar limit and to explode as Type Ia supernovae (SNe Ia). We have investigated their contribution to the overall SN Ia birth rate and found that such SNe Ia tend to be relatively young with typical time delays between 0.1 and 1 Gyr, where some may be as young as 30 Myr. SNe Ia from hybrid CONe WDs may contribute several percent to all SNe Ia, depending on the common-envelope ejection efficiency and the CBR. We suggest that these SNe Ia may produce part of the 2002cx-like SN Ia class.