Point-symmetry in SNR G1.9+0.3: A supernova that destroyed its planetary nebula progenitor

TL;DR

This study reveals a point-symmetrical structure in the youngest Galactic supernova remnant G1.9+0.3, suggesting it exploded within a planetary nebula, supporting the core degenerate scenario for Type Ia supernovae.

Contribution

It provides new evidence linking the morphology of SNR G1.9+0.3 to a planetary nebula progenitor, supporting the core degenerate model of Type Ia supernovae.

Findings

Identification of a point-symmetrical structure in SNR G1.9+0.3

Evidence for a massive circumstellar medium (>1 solar mass)

Support for the explosion within a planetary nebula (PN)

Abstract

I analyze a new X-ray image of the youngest supernova remnant (SNR) in the Galaxy, which is the type Ia SNR G1.9+0.3, and reveal a very clear point-symmetrical structure. Since explosion models of type Ia supernovae (SNe Ia) do not form such morphologies, the point-symmetrical morphology must come from the circumstellar material (CSM) into which the ejecta expands. The large-scale point-symmetry that I identify and the known substantial deceleration of the ejecta of SNR G1.9+0.3 suggest a relatively massive CSM of >1Mo. I argue that the most likely explanation is the explosion of this SN Ia into a planetary nebula (PN). The scenario that predicts a large fraction of SN Ia inside PNe (SNIPs) is the core degenerate scenario. Other SN Ia scenarios might lead to only a very small fraction of SNIPs or not at all.