HD 202206
The primary component is a G-type main-sequence star with a stellar classification of G6V, indicating it is generating energy through core hydrogen fusion. It is an estimated three billion years old and is spinning with a projected rotational velocity of 2.3 km/s. It is a metal-rich star – what astronomers term the abundance of elements of higher atomic number than helium – which may explain the star's unusually high luminosity for its class. The star has a slightly greater mass and radius compared to the Sun.
Companions
In 2000, analysis of radial velocity measurements of the star revealed the existence of a brown dwarf companion with at least 17 times the mass of Jupiter around the star in an eccentric orbit with a period of around 256 days. Even after the brown dwarf was accounted for, the star still showed a drift in the radial velocity measurements, suggesting another companion in a longer-period orbit. In 2004 after further observations, the parameters of a proposed companion was announced.
Further observation of this system revised this picture in 2017, showing that the system instead consisted of a pair of co-orbiting stars being viewed nearly face-on, with the pair being orbited in turn by a Super-Jupiter designated HD 202206 c. The secondary stellar companion, now designated component B rather than 'b', is a red dwarf star with 8.9% of the mass of the Sun.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| c | 17.9+2.9 −1.8 MJ |
2.41 | 1,260±11 | 0.22±0.03 | 7.7±1.1° | — |
References
- ^ 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.
- ^ Benedict, G. Fritz; Harrison, Thomas E. (June 2017). "HD 202206: A Circumbinary Brown Dwarf System". The Astronomical Journal. 153 (6): 12. arXiv:1705.00659. Bibcode:2017AJ....153..258B. doi:10.3847/1538-3881/aa6d59. S2CID 119105717. 258.
- ^ Houk, N.; Smith-Moore, M. (1988). Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars. Vol. 4. Bibcode:1988mcts.book.....H.
- ^ 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. S2CID 119257644.
- ^ Valenti, Jeff A.; Fischer, Debra A. (2005). "Spectroscopic Properties of Cool Stars (SPOCS). I. 1040 F, G, and K Dwarfs from Keck, Lick, and AAT Planet Search Programs". The Astrophysical Journal Supplement Series. 159 (1): 141–166. Bibcode:2005ApJS..159..141V. doi:10.1086/430500.
- ^ "HD 202206". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-07-05.
- ^ Udry, S.; et al. (2002). "The CORALIE survey for southern extra-solar planets VIII. The very low-mass companions of HD 141937, HD 162020, HD 168443, HD 202206: Brown dwarfs or "superplanets"?". Astronomy and Astrophysics. 390 (1): 267–279. arXiv:astro-ph/0202458. Bibcode:2002A&A...390..267U. doi:10.1051/0004-6361:20020685. S2CID 9389274.
- ^ "Exoplanets Galore!" (Press release). Garching, Germany: European Southern Observatory. April 15, 2000. Retrieved December 30, 2012.
- ^ Correia, A.; et al. (2005). "The CORALIE survey for southern extra-solar planets. XIII. A pair of planets around HD202206 or a circumbinary planet?". Astronomy and Astrophysics. 440 (2): 751–758. arXiv:astro-ph/0411512. Bibcode:2005A&A...440..751C. doi:10.1051/0004-6361:20042376. S2CID 16175663.
External links
- HD 202206 Archived 2012-05-27 at the Wayback Machine on Extrasolar Planets Encyclopaedia
- Extrasolar Planet Interactions Archived 2016-05-05 at the Wayback Machine by Rory Barnes & Richard Greenberg, Lunar and Planetary Lab, University of Arizona
