Evidence of a Massive Black Hole Companion in the Massive Eclipsing Binary V Puppis

TL;DR

This paper presents evidence for a massive black hole candidate as a tertiary companion in the eclipsing binary V Puppis, inferred from orbital period variations and lack of spectral lines, suggesting a black hole formed from a supernova.

Contribution

It provides the first evidence of a massive black hole companion in a non-X-ray binary system through orbital period analysis and absence of spectral lines, indicating a new formation pathway.

Findings

Orbital period shows cyclic variation and long-term increase.

Presence of a third body with at least 10.4 solar masses inferred.

No spectral lines detected for the third body, suggesting a black hole.

Abstract

Up to now, most stellar-mass black holes were discovered in X-ray emitting binaries, in which the black holes are formed through a common-envelope evolu tion. Here we give evidence for the presence of a massive black hole candidate as a tertiary companion in the massive eclipsing binary V Puppis. We found that the orbital period of this short-period binary (P=1.45 days) shows a periodic variation while it undergoes a long-term increase. The cyclic period oscillation can be interpreted by the light-travel time effect via the presence of a third body with a mass no less than 10.4 solar mass. However, no spectral lines of the third body were discovered indicating that it is a massive black hole candidate. The black hole candidate may correspond to the weak X-ray source close to V Puppis discovered by Uhuru, Copernicus, and ROSAT satellites produced by accreting materials from the massive binary via stellar wind. The circumstellar matter with many heavy elements around this binary may be formed by the supernova explosion of the progenitor of the massive black hole. All of the observations suggest that a massive black hole is orbiting the massive close binary V Puppis with a period of 5.47 years. Meanwhile, we found the central close binary is undergoing slow mass transfer from the secondary to the primary star on a nuclear time scale of the secondary component, revealing that the system has passed through a rapid mass-transfer stage.