IC 10 X-1: A Double Black Hole Progenitor Probably Formed through Stable Mass Transfer

TL;DR

This study suggests that IC 10 X-1, a close X-ray binary with a Wolf-Rayet donor, likely contains a black hole formed through stable mass transfer, challenging previous assumptions about its formation involving common envelope evolution.

Contribution

The paper introduces new criteria for mass-transfer stability, enabling the formation of IC 10 X-1 like systems without common envelope evolution, using binary population synthesis simulations.

Findings

The compact object in IC 10 X-1 is a black hole of 10-30 solar masses.

Stable mass transfer likely played a key role in the binary's evolution.

Formation without common envelope evolution is possible under new stability criteria.

Abstract

IC 10 X-1 is one of close X-ray binaries containing a Wolf-Rayet donor, which can provide an evolutionary link between high-mass X-ray binaries and gravitational wave sources. It is still unclear about the precise nature of the accreting compact object in IC 10 X-1, although it looks more like a black hole than a neutron star. In this work, we use a binary population synthesis method to simulate the formation of IC 10 X-1 like binaries by assuming different common-envelope ejection efficiencies. This work represents a big step forward over previous studies since we adopt new criteria of mass-transfer stability. These criteria allow the formation of IC 10 X-1 like systems without experiencing common envelope evolution. Based on our calculations, we propose that the compact object in IC 10 X-1 is a black hole with mass of $\sim 10-30M_\odot$ and the progenitor evolution of this binary probably just experienced stable mass transfer.