Gaia BH1 (Gaia DR3 4373465352415301632) is a binary system consisting of a G-type main-sequence star and a likely stellar-mass black hole, located about 1,560 light-years (478 pc) away from the Solar System in the constellation of Ophiuchus.[4] As of May 2024[update], it is the nearest known system that astronomers are reasonably confident contains a black hole, followed by Gaia BH3, Gaia BH2 and A0620-00.[3][5]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ophiuchus[1] |
| Right ascension | 17h 28m 41.09661s[2] |
| Declination | −00° 34′ 51.5234″[2] |
| Characteristics | |
| Sun-like star | |
| Evolutionary stage | Main sequence |
| Spectral type | G[3] |
| Apparent magnitude (G) | 13.77[3] |
| Black hole | |
| Evolutionary stage | Stellar black hole |
| Astrometry | |
| Radial velocity (Rv) | 23.03±2.63[2] km/s |
| Proper motion (μ) | RA: −7.70±0.020 mas/yr[3] Dec.: −25.85±0.027 mas/yr[3] |
| Parallax (π) | 2.09 ± 0.02 mas[3] |
| Distance | 1,560 ± 10 ly (478 ± 5 pc) |
| Orbit[3] | |
| Period (P) | 185.59±0.05 d |
| Semi-major axis (a) | 1.40±0.01 AU |
| Eccentricity (e) | 0.451±0.005 |
| Inclination (i) | 126.6±0.4° |
| Longitude of the node (Ω) | 97.8±1.0° |
| Periastron epoch (T) | 2457387.9±0.7 |
| Argument of periastron (ω) (secondary) | 12.8±1.1° |
| Details[3] | |
| Sun-like star | |
| Mass | 0.93±0.05 M☉ |
| Radius | 0.99±0.05 R☉ |
| Luminosity (bolometric) | 1.06±0.04 L☉ |
| Surface gravity (log g) | 4.55±0.16 cgs |
| Temperature | 5850±50 K |
| Metallicity [Fe/H] | −0.2±0.05 dex |
| Rotational velocity (v sin i) | <3.5 km/s |
| Black hole | |
| Mass | 9.62±0.18 M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
Characteristics
edit
The star and black hole orbit each other with a period of 185.59 days and an eccentricity of 0.45. The star is similar to the Sun, with about 0.93 M☉ and 0.99 R☉, and a temperature of about 5,850 K (5,580 °C; 10,070 °F), while the black hole has a mass of about 9.62 M☉.[3] Given this mass, the black hole's Schwarzschild radius should be about 28 km (17 mi).
Discovery
editGaia BH1 was discovered in 2022 via astrometric observations with Gaia, and also observed via radial velocity. The discovery team found no astrophysical scenario that could explain the observed motion of the G-type star, other than a black hole. The system differs from "black hole impostors" such as LB-1 and HR 6819 in that the evidence for a black hole does not depend on the mass of the star or the inclination of the orbit, and there is no evidence of mass transfer.[3] The discovery team also found a second system that is a candidate for containing a black hole, which was also reported by another team of astronomers,[3][6] and was confirmed in 2023 as Gaia BH2.[7]
The black hole was also independently detected by a second team, who found slightly different parameters.[8]
See also
editReferences
edit- ^ "Finding the constellation which contains given sky coordinates". djm.cc. 2 August 2008.
- ^ 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.
- ^ a b c d e f g h i j k El-Badry, Kareem; Rix, Hans-Walter; et al. (2 November 2022). "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.
- ^ Overbye, Dennis (5 November 2022). "Astronomers Find a Black Hole in Our Cosmic Back Yard - Just 1,600 light-years away, the black hole is the closest known to Earth. The good news: It's dormant, at least for now". The New York Times. Retrieved 6 November 2022.
- ^ "Astronomers Discover Closest Black Hole to Earth". noirlab.edu. NOIRLab. 4 November 2022. Retrieved 4 November 2022.
- ^ Tanikawa, Ataru; Hattori, Kohei; et al. (2023). "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.
- ^ El-Badry, Kareem; Rix, Hans-Walter; et al. (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.
- ^ Chakrabarti, Sukanya; Simon, Joshua D.; et al. (2023). "A Noninteracting Galactic Black Hole Candidate in a Binary System with a Main-sequence Star". The Astronomical Journal. 166 (1): 6. arXiv:2210.05003. Bibcode:2023AJ....166....6C. doi:10.3847/1538-3881/accf21.