Shenar, Tomer ; Sana, Hugues ; Mahy, Laurent ; El-Badry, Kareem ; Marchant, Pablo ; Langer, Norbert ; Hawcroft, Calum ; Fabry, Matthias ; Sen, Koushik ; Almeida, Leonardo A. ; Abdul-Masih, Michael ; Bodensteiner, Julia ; Crowther, Paul A. ; Gieles, Mark ; Gromadzki, Mariusz ; Hénault-Brunet, Vincent ; Herrero, Artemio ; de Koter, Alex ; Iwanek, Patryk ; Kozłowski, Szymon ; Lennon, Daniel J. ; Maíz Apellániz, Jesús ; Mróz, Przemysław ; Moffat, Anthony F. J. ; Picco, Annachiara ; Pietrukowicz, Paweł ; Poleski, Radosław ; Rybicki, Krzysztof ; Schneider, Fabian R. N. ; Skowron, Dorota M. ; Skowron, Jan ; Soszyński, Igor ; Szymański, Michał K. ; Toonen, Silvia ; Udalski, Andrzej ; Ulaczyk, Krzysztof ; Vink, Jorick S. ; Wrona, Marcin

published in Nature Astronomy, 6, pp. 1085-1092 (2022)

Abstract: Stellar-mass black holes are the final remnants of stars born with more than 15 solar masses. Billions are expected to reside in the Local Group, yet only a few are known, mostly detected through X-rays emitted as they accrete material from a companion star. Here, we report on VFTS 243: a massive X-ray-faint binary in the Large Magellanic Cloud. With an orbital period of 10.4 d, it comprises an O-type star of 25 solar masses and an unseen companion of at least nine solar masses. Our spectral analysis excludes a non-degenerate companion at a 5σ confidence level. The minimum companion mass implies that it is a black hole. No other X-ray-quiet black hole is unambiguously known outside our Galaxy. The (near-)circular orbit and kinematics of VFTS 243 imply that the collapse of the progenitor into a black hole was associated with little or no ejected material or black-hole kick. Identifying such unique binaries substantially impacts the predicted rates of gravitational-wave detections and properties of core-collapse supernovae across the cosmos.

Keyword(s): Astrophysics - High Energy Astrophysical Phenomena ; Astrophysics - Astrophysics of Galaxies ; Astrophysics - Solar and Stellar Astrophysics
DOI: 10.1038/s41550-022-01730-y