Stellar Binaries That Survive Supernovae

TL;DR

This study searches for surviving star-remnant binaries in supernova remnants, finding very few, which constrains the fraction of binaries that survive supernovae and aligns with population synthesis models.

Contribution

First observational constraints on the fraction of binaries surviving supernova explosions, supporting binary population synthesis predictions.

Findings

Less than 10% of core-collapse SNRs contain non-interacting binaries.

Approximately 8.3% contain an interacting binary at 90% confidence.

Surviving binaries tend to be close to explosion centers with low transverse velocities.

Abstract

The number of binaries containing black holes or neutron stars depends critically on the fraction of binaries that survive supernova explosions. We searched for surviving star plus remnant binaries in a sample of 49 supernova remnants (SNR) containing 23 previously identified compact remnants and three high mass X-ray binaries (HMXB), finding no new interacting or non-interacting binaries. The upper limits on any main sequence stellar companion are typically <0.2Msun and are at worst <3Msun. This implies that f<0.1 of core collapse SNRs contain a non-interacting binary, and f=0.083 (0.032<f<0.17) contain an interacting binary at 90% confidence. We also find that the transverse velocities of HMXBs are low, with a median of only 12~km/s for field HMXBs, so surviving binaries will generally be found very close to the explosion center. We compare the results to a "standard" StarTrack binary population synthesis (BPS) model, finding reasonable agreement with the observations. In particular, the BPS models predict that 5% of SNe should leave a star plus remnant binary.