Do Type Ia Supernovae Explode Inside Planetary Nebulae?

TL;DR

This study investigates whether Type Ia supernovae can occur inside planetary nebulae by simulating their interaction and comparing results with observed supernova remnants, finding that longer delays after the common envelope phase better match observations.

Contribution

It introduces hydrodynamic and ionization simulations of SN Ia explosions within planetary nebulae, analyzing the impact of delay times on observable properties and matching with real remnants.

Findings

Immediate post-CE explosions are inconsistent with observed SNR ionization timescales.

Longer delays (~10,000 yr) produce SNR properties closer to observations.

Models with longer delays can potentially explain some observed Type Ia SNRs.

Abstract

The nature of Type Ia Supernova (SN Ia) explosions remains an open issue, with several contending progenitor scenarios actively being considered. One such scenario involves a SN Ia explosion inside a planetary nebula (PN) in the aftermath of a stellar merger triggered by a common envelope (CE) episode. We examine this scenario using hydrodynamic and non-equilibrium ionization simulations of the interaction between the SN ejecta and the PN cocoon into the supernova remnant (SNR) phase, focusing on the impact of the delay between the CE episode and the SN explosion. We compare the bulk dynamics and X-ray spectra of our simulated SNRs to the observed properties of known Type Ia SNRs in the Milky Way and the Magellanic Clouds. We conclude that models where the SN explosion happens in the immediate aftermath of the CE episode (with a delay $\lesssim$1,000 yr) are hard to reconcile with the observations, because the interaction with the dense PN cocoon results in ionization timescales much higher than those found in any known Type Ia SNR. Models with a longer delay between the CE episode and the SN explosion ($\sim$10,000 yr) are closer to the observations, and may be able to explain the bulk properties of some Type Ia SNRs.