Progenitors of ultra-stripped supernovae

TL;DR

This paper investigates the evolution of helium star companions to neutron stars leading to ultra-stripped supernovae, highlighting their unique properties and significance for binary pulsars and gravitational wave sources.

Contribution

It provides a systematic analysis of progenitor evolution for ultra-stripped supernovae, including their pre-explosion structures and observational characteristics.

Findings

Progenitors can have extremely low-mass envelopes (<0.01 Msun).

Ultra-stripped SNe likely produce low-kick neutron stars in the 1.10-1.80 Msun range.

The study distinguishes between electron-capture and iron core-collapse supernovae.

Abstract

The explosion of ultra-stripped stars in close binaries may explain new discoveries of weak and fast optical transients. We have demonstrated that helium star companions to neutron stars (NSs) may evolve into naked metal cores as low as ~1.5 Msun, barely above the Chandrasekhar mass limit, by the time they explode. Here we present a new systematic investigation of the progenitor evolution leading to such ultra-stripped supernovae (SNe), in some cases yielding pre-SN envelopes of less than 0.01 Msun. We discuss the nature of these SNe (electron-capture vs iron core-collapse) and their observational light-curve properties. Ultra-stripped SNe are highly relevant for binary pulsars, as well as gravitational wave detection of merging NSs by LIGO/VIRGO, since these events are expected to produce mainly low-kick NSs in the mass range 1.10-1.80 Msun.