Year: 2024
Type: article
Abstract: Context. The black holes discovered using Gaia, especially Gaia BH1 and BH2, have low-mass companions of solar-like metallicity in wide orbits. For standard formation channels of isolated binary evolution that include interactions, this extreme mass ratio is unexpected, especially for orbits of hundreds to thousands of days. Aims. We investigate a non-interacting formation path for isolated binaries to explain the formation of Gaia BH1 and BH2. Methods. We used single star models computed with MESA to constrain the main characteristics of possible progenitors of long-period black hole binaries such as Gaia BH1 and BH2. Then, we incorporated these model grids into the binary population synthesis code POSYDON to explore whether the formation of the observed binaries at solar metallicity is indeed possible. Results. We find that winds of massive stars (≳80 M⊙), especially during the Wolf-Rayet phase, tend to cause a plateau in the relation of the initial stellar mass to final black hole mass (at about 13 M⊙ in our default wind prescription). However, stellar winds at earlier evolutionary phases are also important at high metallicity, as they prevent the most massive stars from expanding (< 100 R⊙) and filling their Roche lobe. Consequently, the strength of the applied winds affects the range of the final black hole masses in non-interacting binaries, which enables the formation of systems similar to Gaia BH1 and BH2. Conclusions. We deduce that wide binaries with a black hole and a low-mass companion can form at high metallicity without binary interactions. There could be hundreds of such systems in the Milky Way. The mass of the black hole in binaries that evolved through the non-interacting channel might provide insights into the wind strength during the progenitor evolution.
Source: Astronomy and Astrophysics
Institutions: University of Geneva, University of Florida, Northwestern University, Institute of Space Sciences, Institut d'Estudis Espacials de Catalunya, National Observatory of Athens, FORTH Institute of Astrophysics, Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, Foundation for Research and Technology Hellas
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,732
Funders: National Science Foundation, National Aeronautics and Space Administration, Gordon and Betty Moore Foundation, Space Telescope Science Institute, Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung, China Scholarship Council, Hellenic Foundation for Research and Innovation, Agencia Estatal de Investigación
Awards: G103270039, G256731684, CyberTraining: CIU: The LSST Data Science Fellowship Program, Compact-Object-Formation Forensics in the Era of Gravitational Waves, Which Stars Lead to Black Hole Collisions?, G5074879826, G5859628442, G617610489, GW-Learn: Deciphering the Gravitation-Wave Universe using the Next-Generation Observatories and Machine Learning
OpenAlex ID: W4404133541