Gaia BH2 (Gaia DR3 5870569352746779008) is a binary system consisting of a red giant and what is very likely a stellar-mass black hole. Gaia BH2 is located about 3,800 light years away (1.16 kpc away) in the constellation of Centaurus, making it as of 2024 the third-closest known black hole system to Earth. Gaia BH2 is the second black hole discovered from Gaia DR3 astrometric data.[3]

The black hole and red giant orbit the system barycentre every 1,277 days, or around 3.5 years, with a moderate eccentricity of 0.518. The black hole's mass is around 8.94 M☉, which means its Schwarzschild radius should be about 26.4 km (16.4 mi). The red giant has a mass of 1.07 M☉ and a radius of 7.77 R☉. Its temperature is estimated at 4,604 K (4,331 °C; 7,828 °F).[3]

Discovery

Gaia BH2 was originally discovered as a black hole binary candidate in 2022, found via astrometric observations with Gaia, along with Gaia BH1. At that time it was not clear if Gaia BH2 did definitely harbour a black hole, but it was the only plausible candidate in the Gaia data other than Gaia BH1.[4][5] Later radial velocity observations confirmed this black hole system and refined its orbital parameters.[3]

References

  1. ^ a b c Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ^ Zacharias, N.; Finch, C. T.; Girard, T. M.; Henden, A.; Bartlett, J. L.; Monet, D. G.; Zacharias, M. I. (2012-07-01). "VizieR Online Data Catalog: UCAC4 Catalogue (Zacharias+, 2012)". VizieR Online Data Catalog: I/322A. Bibcode:2012yCat.1322....0Z.
  3. ^ a b c d e f g El-Badry, Kareem; Rix, Hans-Walter; Cendes, Yvette; Rodriguez, Antonio C.; Conroy, Charlie; Quataert, Eliot; Hawkins, Keith; Zari, Eleonora; Hobson, Melissa; Breivik, Katelyn; Rau, Arne; Berger, Edo; Shahaf, Sahar; Seeburger, Rhys; Burdge, Kevin B. (2023-02-01). "A red giant orbiting a black hole". Monthly Notices of the Royal Astronomical Society. 521 (3): 4323–4348. arXiv:2302.07880. Bibcode:2023MNRAS.521.4323E. doi:10.1093/mnras/stad799.
  4. ^ El-Badry, Kareem; Rix, Hans-Walter; Quataert, Eliot; Howard, Andrew W.; Isaacson, Howard; Fuller, Jim; Hawkins, Keith; Breivik, Katelyn; Wong, Kaze W. K.; Rodriguez, Antonio C.; Conroy, Charlie; Shahaf, Sahar; Mazeh, Tsevi; Arenou, Frédéric; Burdge, Kevin B. (2023-01-01). "A Sun-like star orbiting a black hole". Monthly Notices of the Royal Astronomical Society. 518 (1): 1057–1085. arXiv:2209.06833. Bibcode:2023MNRAS.518.1057E. doi:10.1093/mnras/stac3140. ISSN 0035-8711.
  5. ^ Tanikawa, Ataru; Hattori, Kohei; et al. (September 2022). "Search for a Black Hole Binary in Gaia DR3 Astrometric Binary Stars with Spectroscopic Data". The Astrophysical Journal. 946 (2): 79. arXiv:2209.05632. Bibcode:2023ApJ...946...79T. doi:10.3847/1538-4357/acbf36.
Allikas: https://en.wikipedia.org/wiki/Gaia_BH2
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