Do SN 2002cx-like and SN Ia-CSM objects share the same origin?

TL;DR

This paper proposes a unified progenitor model for SN 2002cx-like and SN Ia-CSM supernovae, suggesting they originate from hybrid CONe white dwarfs in single-degenerate systems with varying common envelope properties.

Contribution

It introduces a common progenitor framework using the CEW model, explaining the similarities and differences between these supernova subclasses and predicting their relative frequencies.

Findings

Estimated ratio of SN Ia-CSM to SN 2002cx-like objects matches observations.

Model predicts a sequence of CSM densities from SN Ia-CSM to normal SNe Ia.

Identifies a new subclass of hybrid SNe with properties of Type II and Ia SNe.

Abstract

SN 2002cx-like and SN Ia-CSM objects show similar early spectra and both belong to a young stellar population, suggesting that they could share the same progenitor origin. Adopting the framework of the common-envelope-wind (CEW) model developed in \citet{MENGXC17}, we here propose that both subclasses of SNe Ia are caused by the explosion of hybrid carbon-oxygen-neon white dwarfs (CONe WDs) in single-degenerate systems, where SNe Ia-CSM explode in systems with a massive common envelope (CE) of $\sim1~M_{\odot}$, while SN 2002cx-like events correspond to those events where most of the CE has been lost in a wind. Using binary-population-synthesis (BPS) calculations, we estimate a number ratio of SNe Ia-CSM to SN 2002cx-like objects between $\frac{1}{3}$ and $\frac{2}{3}$, consistent with observational constraints, and an overall contribution from hybrid CONe WDs to the total SN Ia population that also matches the observed number from these peculiar objects. Our model predicts a statistical sequence of CSM density from SN Ia-CSM to SN 2002cx-like events and normal SNe Ia, consistent with existing radio constraints. We also find a new subclass of hybrid SNe which share the properties of Type II and Type Ia SNe, consistent with some observed SNe, which do not have a surviving companion. In some cases these could even produce SNe Ia from apparently single WDs.