Phase-resolved spectroscopic analysis of the eclipsing black hole X-ray binary M33 X-7: System properties, accretion, and evolution
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http://hdl.handle.net/10045/129634
Títol: | Phase-resolved spectroscopic analysis of the eclipsing black hole X-ray binary M33 X-7: System properties, accretion, and evolution |
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Autors: | Ramachandran, Varsha | Oskinova, Lidia M. | Hamann, Wolf-Rainer | Sander, Andreas | Todt, Helge | Pauli, Daniel | Shenar, Tomer | Torrejon, Jose M. | Postnov, Konstantin | Blondin, John M. | Bozzo, Enrico | Hainich, Rainer | Massa, Derck |
Grups d'investigació o GITE: | Astronomía y Astrofísica |
Centre, Departament o Servei: | Universidad de Alicante. Departamento de Física, Ingeniería de Sistemas y Teoría de la Señal | Universidad de Alicante. Instituto Universitario de Física Aplicada a las Ciencias y las Tecnologías |
Paraules clau: | Stars: black holes | Stars: massive | Stars: winds | Outflows | X-rays: binaries | Stars: fundamental parameters | Stars: evolution |
Data de publicació: | 11-de novembre-2022 |
Editor: | EDP Sciences |
Citació bibliogràfica: | Astronomy & Astrophysics. 2022, 667: A77. https://doi.org/10.1051/0004-6361/202243683 |
Resum: | M33 X-7 is the only known eclipsing black hole high mass X-ray binary. The system is reported to contain a very massive O supergiant donor and a massive black hole in a short orbit. The high X-ray luminosity and its location in the metal-poor galaxy M33 make it a unique laboratory for studying the winds of metal-poor donor stars with black hole companions and it helps us to understand the potential progenitors of black hole mergers. Using phase-resolved simultaneous HST- and XMM-Newton-observations, we traced the interaction of the stellar wind with the black hole. We observed a strong Hatchett-McCray effect in M33 X-7 for the full range of wind velocities. Our comprehensive spectroscopic investigation of the donor star (X-ray+UV+optical) yields new stellar and wind parameters for the system that differ significantly from previous estimates. In particular, the masses of the components are considerably reduced to ≈38 M⊙ for the O-star donor and ≈11.4 M⊙ for the black hole. The O giant is overfilling its Roche lobe and shows surface He enrichment. The donor shows a densely clumped wind with a mass-loss rate that matches theoretical predictions. An extended ionization zone is even present during the eclipse due to scattered X-ray photons. The X-ray ionization zone extends close to the photosphere of the donor during inferior conjunction. We investigated the wind-driving contributions from different ions and the changes in the ionization structure due to X-ray illumination. Toward the black hole, the wind is strongly quenched due to strong X-ray illumination. For this system, the standard wind-fed accretion scenario alone cannot explain the observed X-ray luminosity, pointing toward an additional mass overflow, which is in line with our acceleration calculations. The X-ray photoionization creates an He II emission region around the system emitting ∼1047 ph s−1. We computed binary evolutionary tracks for the system using MESA. Currently, the system is transitioning toward an unstable mass transfer phase, possibly resulting in a common envelope of the black hole and the O-star donor. Since the mass ratio is q ≳ 3.3 and the period is short, the system is unlikely to survive the common envelope, but will rather merge. |
Patrocinadors: | VR acknowledges support by the Deutsches Zentrum fsür Luft- und Raumfahrt (DLR) under grant 50 OR 1912. VR and AACS acknowledge support by the Deutsche Forschungsgemeinschaft (DFG – German Research Foundation) in the form of an Emmy Noether Research Group (grant number SA4064/1-1, PI Sander). DP acknowledges financial support by the Deutsches Zentrum für Luft und Raumfahrt (DLR) grant FKZ 50 OR 2005. |
URI: | http://hdl.handle.net/10045/129634 |
ISSN: | 0004-6361 (Print) | 1432-0746 (Online) |
DOI: | 10.1051/0004-6361/202243683 |
Idioma: | eng |
Tipus: | info:eu-repo/semantics/article |
Drets: | © V. Ramachandran et al. 2022. Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
Revisió científica: | si |
Versió de l'editor: | https://doi.org/10.1051/0004-6361/202243683 |
Apareix a la col·lecció: | INV - Astronomía y Astrofísica - Artículos de Revistas |
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