The center of the Type Ia supernova remnant SNR 0509-67.5 is empty of any ex-companion star to M_V=+8.4

TL;DR

This study finds no ex-companion star in the center of SNR 0509-67.5 down to a deep magnitude limit, strongly supporting the double-degenerate progenitor model for this Type Ia supernova.

Contribution

It provides the first deep, conclusive observational evidence ruling out single-degenerate progenitors for SNR 0509-67.5, favoring the double-degenerate scenario.

Findings

No ex-companion star detected within the 99.73% confidence region.

Deep magnitude limit of V=26.9 (M_V=+8.4) set for potential ex-companions.

Supports double-degenerate origin for this Type Ia supernova.

Abstract

Type Ia supernova (SNe Ia) are thought to originate in the explosion of a white dwarf. The explosion could be triggered by the merger of two white dwarfs ('double-degenerate' origin), or by mass transfer from a companion star (the 'single-degenerate' path). The identity of the progenitor is still controversial; for example, a recent argument against the single-degenerate origin has been widely rejected. One way to distinguish between the double- and single-degenerate progenitors is to look at the center of a known SN Ia remnant to see whether any former companion star is present. A likely ex-companion star for the progenitor of Tycho's supernova has been identified, but that claim is still controversial. Here we report that the central region of the supernova remnant SNR 0509-67.5 (the site of a Type Ia supernova 400+-50 years ago, based on its light echo) in the Large Magellanic Cloud contains no ex-companion star to a limit of V=26.9 magnitude (M_V=+8.4) within the extreme 99.73% region with radius 1.43". The lack of any ex-companion star to deep limits rules out all published single-degenerate models. The only remaining possibility is that the progenitor for this particular SN Ia was a double-degenerate system.