On the Progenitor System of the Type Iax Supernova 2014dt in M61

TL;DR

This study uses pre- and post-explosion Hubble images to constrain the progenitor system of SN 2014dt, suggesting it was likely a white dwarf with a helium-star or low-mass star companion, but not a massive star.

Contribution

First deep limits on the progenitor of a Type Iax supernova in M61, narrowing down possible progenitor systems and ruling out most massive stars.

Findings

No progenitor detected at the SN location in pre-explosion images.

Progenitor consistent with a C/O white dwarf and helium-star companion.

Massive stars (>16 M_sun) are ruled out as progenitors.

Abstract

We present pre-explosion and post-explosion Hubble Space Telescope images of the Type Iax supernova (SN Iax) 2014dt in M61. After astrometrically aligning these images, we do not detect any stellar sources at the position of the SN in the pre-explosion images to relatively deep limits (3 sigma limits of M_F438W > -5.0 mag and M_F814W > -5.9 mag). These limits are similar to the luminosity of SN 2012Z's progenitor system (M_F435W = -5.43 +/- 0.15 and M_F814W = -5.24 +/- 0.16 mag), the only probable detected progenitor system in pre-explosion images of a SN Iax, and indeed, of any white dwarf supernova. SN 2014dt is consistent with having a C/O white-dwarf primary/helium-star companion progenitor system, as was suggested for SN 2012Z, although perhaps with a slightly smaller or hotter donor. The data are also consistent with SN 2014dt having a low-mass red giant or main-sequence star companion. The data rule out main-sequence stars with M_init > 16 M_sun and most evolved stars with M_init > 8 M_sun as being the progenitor of SN 2014dt. Hot Wolf-Rayet stars are also allowed, but the lack of nearby bright sources makes this scenario unlikely. Because of its proximity (D = 12 Mpc), SN 2014dt is ideal for long-term monitoring, where images in ~2 years may detect the companion star or the luminous bound remnant of the progenitor white dwarf.