Possible white dwarf progenitors of type Ia supernovae

TL;DR

This paper investigates whether the core degenerate scenario involving massive white dwarfs can account for all type Ia supernovae, finding sufficient numbers of massive white dwarfs to support this hypothesis.

Contribution

It demonstrates that the number of massive white dwarfs is compatible with the core degenerate scenario being the primary cause of type Ia supernovae.

Findings

Approximately 0.2% of current white dwarfs are massive enough to explode as SNe Ia.

The observed fraction of massive white dwarfs is 1-3%, exceeding the minimum needed for the scenario.

The core degenerate scenario remains a viable explanation for SNe Ia.

Abstract

We examine catalogs of white dwarfs (WDs) and find that there are sufficient number of massive WDs, M_WD > 1.35Mo, that might potentially explode as type Ia supernovae (SNe Ia) in the frame of the core degenerate scenario. In the core degenerate scenario a WD merges with the carbon-oxygen core of a giant star, and they form a massive WD that might explode with a time delay of years to billions of years. If the core degenerate scenario accounts for all SNe Ia, then we calculate that about 0.2 per cent of the present WDs in the Galaxy are massive. Furthermore, we find from the catalogs that the fraction of massive WDs relative to all WDs is about 1-3 per cent, with large uncertainties. Namely, five to ten times the required number. If there are many SNe Ia that result from lower mass WDs, M_WD < 1.3Mo, for which another scenario is responsible for, and the core degenerate scenario accounts only for the SNe Ia that explode as massive WDs, then the ratio of observed massive WDs to required is larger even. Our finding leaves the core degenerate scenario as a viable and promising SN Ia scenario.