HR 6819
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Telescopium |
| Right ascension | 18h 17m 07.53179s[1] |
| Declination | −56° 01′ 24.0876″[1] |
| Apparent magnitude (V) | 5.36[2] (5.31 to 5.38)[3] |
| Characteristics | |
| Evolutionary stage | giant |
| Spectral type | B3IIIpe[4] or B3II/III[5] |
| B−V color index | −0.050±0.018[2] |
| Variable type | Be[3] |
| Astrometry | |
| Radial velocity (Rv) | +9.4±0.5[6] km/s |
| Proper motion (μ) | RA: -3.667[1] mas/yr Dec.: +11.120[1] mas/yr |
| Parallax (π) | 2.9148 ± 0.1828 mas[1] |
| Distance | 1,120 ± 70 ly (340 ± 20 pc) |
| Absolute magnitude (MV) | −1.47[2]/∞BH/−0.5[6] |
| Orbit[6] | |
| Primary | QV Tel Aa |
| Companion | QV Tel Ab |
| Period (P) | 40.333±0.004 d |
| Eccentricity (e) | 0.03±0.01 |
| Argument of periastron (ω) (secondary) | 89° |
| Semi-amplitude (K1) (primary) | 61.3±0.6 km/s |
| Details[7] | |
| QV Tel Aa | |
| Mass | 6.3±0.1[8] M☉ |
| Radius | 3.90±0.08[7] R☉ |
| Luminosity | 449.33[2] L☉ |
| Surface gravity (log g) | 3.80±0.04[7] cgs |
| Temperature | 20,000±200[7] K |
| Rotational velocity (v sin i) | 50±1[7] km/s |
| Age | 50.1±4.6[8] Myr |
| QV Tel Ab | |
| Mass | ≥5.0 ± 0.4[6] M☉ |
| QV Tel B | |
| Other designations | |
| Database references | |
| SIMBAD | data |
QV Telescopii is a triple star system in the southern constellation of Telescopium, near the southern constellation boundary with Pavo. QV Tel is the variable star designation,[10] while the star system is also designated under various identifiers such as HD 167128 and HR 6819.[9] The system appears as a variable star that is dimly visible to the naked eye with an apparent magnitude that ranges from 5.31 down to 5.38.[3] It is located at a distance of approximately 1,120 light years from the Sun,[1] and is drifting farther away at a rate of 15 km/s.[2] A May 2020 study reported it to contain a black hole, making it the closest known black hole, and the first one located in a stellar system visible to the naked eye.[6]
Components
QV Telescopii is a hierarchical triple containing a classical Be star in a wide orbit of unknown period around an inner 40.3 day binary, a B3 III star and a nonemitting (nonaccreting) black hole (≥5±0.4 M☉), termed as Ab.[6]
Previously considered a single star,[11] the multiplicity of QV Telescopii was discovered through radial velocity measurements in 2020, which suggested the presence of an unseen stellar-mass black hole within the system.[6] Though the QV Telescopii system has been described as a member of the Sco OB2 association of co-moving stars,[12] it has more recently been suggested to be an older system and not part of the association.[6]
QV Tel Aa
Termed Aa, the main, inner stellar component is a B3 III blue giant star, which orbits the black hole as a binary, with an orbital period of 40.3 days.
QV Tel B
The second, outer stellar component termed as B is a Be star with a stellar classification of B3IIIpe.[4] The 'e' suffix indicates emission lines in its spectrum. It is a rapidly rotating blue-white star with a hot disk of decreted gas surrounding it.[13] Samus et al. (2017) catalogue this star as variable, although not properly of the Gamma Cassiopeiae type.[3] It is an estimated 50 million years in age,[8] with a projected rotational velocity of 50 km/s.[7]
QV Tel Ab, black hole
Radial velocity measurements of the inner component in 2020 suggested the presence of a massive unseen companion, which is hypothesized to be a black hole.[6] Being 1,120 light years distant from the Sun, this would make it the closest known black hole to the Sun and the first and only known black hole system visible with the naked eye at 5.36 apparent magnitude, making it one of the 2,000 brightest stellar systems.[2] The black hole itself is not visible as it does not interact with its companion stars to form an accretion disk.[6]
See also
References
- ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ a b c d e f Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015.
- ^ a b c d Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 5.1. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085.
- ^ a b Hiltner, W. A.; et al. (July 1969). "MK Spectral Types for Bright Southern OB Stars". The Astrophysical Journal. 157: 313. Bibcode:1969ApJ...157..313H. doi:10.1086/150069.
- ^ Houk, Nancy (1979). Michigan catalogue of two-dimensional spectral types for the HD stars. Vol. 1. Ann Arbor, Michigan: Department of Astronomy, University of Michigan. Bibcode:1978mcts.book.....H.
- ^ a b c d e f g h i j k Rivinius, Th.; Baade, D.; Hadrava, P.; Heida, M.; Klement, R. (2020). "A naked-eye triple system with a nonaccreting black hole in the inner binary". Astronomy & Astrophysics. 637 (L3): 11. arXiv:2005.02541. doi:10.1051/0004-6361/202038020.
- ^ a b c d e f Arcos, C.; et al. (March 2018). "Stellar parameters and H α line profile variability of Be stars in the BeSOS survey". Monthly Notices of the Royal Astronomical Society. 474 (4): 5287–5299. arXiv:1711.08675. Bibcode:2018MNRAS.474.5287A. doi:10.1093/mnras/stx3075.
- ^ a b c Tetzlaff, N.; et al. (January 2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1): 190–200. arXiv:1007.4883. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x.
- ^ a b "HD 167128". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-02-14.
- ^ "QV Telescopii". Variable Star Index. Retrieved 2020-05-06.
- ^ Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x.
- ^ Brown, A. G. A.; Verschueren, W. (1997). "High S/N Echelle spectroscopy in young stellar groups. II. Rotational velocities of early-type stars in SCO OB2". Astronomy and Astrophysics. 319: 811. arXiv:astro-ph/9608089. Bibcode:1997A&A...319..811B.
- ^ Jaschek, M.; Egret, D. (April 1982). "Catalog of Be stars". IAU Symposium. 98: 261. Bibcode:1982IAUS...98..261J.
