HD 202206
| Observation data EpochJ2000.0EquinoxJ2000.0 | |
|---|---|
| Constellation | Capricornus |
| Right ascension | 21h14m57.76850s[1] |
| Declination | −20° 47′ 21.1624″[1] |
| Apparent magnitude(V) | +8.07±0.01[2] |
| Characteristics | |
| Spectral type | G6V[3]+ M8V[2] |
| B−Vcolor index | 0.714±0.012[4] |
| Astrometry | |
| Radial velocity(Rv) | +14.68±0.23[5]km/s |
| Proper motion(μ) | RA:−39.079[1]mas/yr Dec.:−119.999[1]mas/yr |
| Parallax(π) | 21.7264 ± 0.0651mas[1] |
| Distance | 150.1 ± 0.4ly (46.0 ± 0.1pc) |
| Absolute magnitude(MV) | +4.80[4] |
| Orbit[2] | |
| Period(P) | 256.33 days |
| Semi-major axis(a) | 1.40±0.10 mas |
| Eccentricity(e) | 0.432±0.001 |
| Inclination(i) | 10.9±0.8° |
| Longitude of the node(Ω) | 121±4° |
| Periastronepoch(T) | 2,452,176.14±0.12JD |
| Argument of periastron(ω) (secondary) | 161.9±0.2° |
| Semi-amplitude(K1) (primary) | 0.567±0.001km/s |
| Details | |
| A | |
| Mass | 1.07±0.08[2]M☉ |
| Radius | 1.05+0.02 −0.03[1]R☉ |
| Luminosity | 1.084+0.004 −0.005[1]L☉ |
| Surface gravity(logg) | 4.5±0.1[2]cgs |
| Temperature | 5,735+76 −74[1]K |
| Metallicity[Fe/H] | 0.29±0.01[4]dex |
| Rotational velocity(vsini) | 2.3±0.5[2]km/s |
| Age | 2.9±1.0[2]Gyr |
| B | |
| Mass | 0.089+0.007 −0.006[2]M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 202206is abinary starsystem in the southernconstellationofCapricornus.With anapparent visual magnitudeof +8.1,[2]it is too faint to be visible to thenakedeye. It is located at a distance of 150light yearsfrom theSunbased onparallax,and is drifting further away with aradial velocityof +14.7 km/s.[5]
The primary component is aG-type main-sequence starwith astellar classificationof G6V,[3]indicating it is generating energy throughcorehydrogen fusion.It is an estimated three[2]billion years old and is spinning with aprojected rotational velocityof 2.3 km/s.[2]It is ametal-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.[7]The star has a slightly greater mass and radius compared to the Sun.[2]
Companions
[edit]In 2000, analysis ofradial velocitymeasurements of the star revealed the existence of abrown dwarfcompanion[8]with at least 17 times the mass ofJupiteraround the star in aneccentricorbit with a period of around 256days.[7]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.[9]
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 designatedHD 202206 c.The secondary stellar companion, now designated component B rather than 'b', is ared dwarfstar with 8.9% of the mass of the Sun.[2]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| c | 17.9+2.9 −1.8MJ |
2.41 | 1,260±11 | 0.22±0.03 | 7.7±1.1° | — |
References
[edit]- ^abcdefghBrown, A. G. A.;et al. (Gaia collaboration) (August 2018)."GaiaData 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 sourceatVizieR.
- ^abcdefghijklmnBenedict, 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.S2CID119105717.258.
- ^abHouk, N.; Smith-Moore, M. (1988).Michigan Catalogue of Two-dimensional Spectral Types for the HD Stars.Vol. 4.Bibcode:1988mcts.book.....H.
- ^abcAnderson, 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.S2CID119257644.
- ^abValenti, 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.Retrieved2020-07-05.
- ^abUdry, 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.S2CID9389274.
- ^"Exoplanets Galore!"(Press release). Garching, Germany:European Southern Observatory.April 15, 2000.RetrievedDecember 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.S2CID16175663.
External links
[edit]- HD 202206Archived2012-05-27 at theWayback MachineonExtrasolar Planets Encyclopaedia
- Extrasolar Planet InteractionsArchived2016-05-05 at theWayback Machineby Rory Barnes & Richard Greenberg, Lunar and Planetary Lab, University of Arizona
