Common envelope to explosion delay time distribution (CEEDTD) of type Ia supernovae

TL;DR

This paper estimates that about half of type Ia supernovae occur inside planetary nebulae shortly after common envelope evolution, suggesting a significant role for the core-degenerate scenario in their origins.

Contribution

It introduces a new delay time distribution from common envelope evolution to supernova explosion, highlighting the core-degenerate scenario as a major pathway.

Findings

Approximately 50% of SNe Ia are inside planetary nebulae.

Most SNIPs explode within about ten thousand years after CEE.

The explosion rate of SNIPs is roughly constant within this time frame.

Abstract

I use recent observations of circumstellar matter (CSM) around type Ia supernovae (SNe Ia) to estimate the fraction of SNe Ia that explode into a planetary nebula (PN) and to suggest a new delay time distribution from the common envelope evolution (CEE) to the SN Ia explosion for SNe Ia that occur shortly after the CEE. Under the assumption that the CSM results from a CEE, I crudely estimate that about 50 per cent of all SNe Ia are SNe Ia inside PNe (SNIPs), and that the explosions of most SNIPs occur within a CEE to explosion delay (CEED) time of less than about ten thousand years. I also estimate that the explosion rate of SNIPs, i.e., the CEED time distribution (CEEDTD), is roughly constant within this time scale of ten thousand years. The short CEED time suggests than a fraction of SNIPs come from the core-degenerate (CD) scenario where the merger of the core with the white dwarf takes place at the end of the CEE. I present my view that the majority of SNIPs come from the CD scenario. I list some further observations that might support or reject my claims, and the challenge to theoretical studies to find a process to explain a merger to explosion delay (MED) time of up to ten thousand years or so. A long MED will apply also to the double degenerate scenario.