HD 20782
Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Fornax |
Right ascension | 03h 20m 03.57776s[1] |
Declination | −28° 51′ 14.6604″[1] |
Apparent magnitude (V) | 7.38[2] |
Characteristics | |
Spectral type | G1.5 V[3] |
B−V color index | +0.65[2] |
Astrometry | |
Radial velocity (Rv) | 40.7±0.99[4] km/s |
Proper motion ( | RA: +349.054 mas/yr[1] Dec.: −65.305 mas/yr[1] |
Parallax ( | 27.8760 ± 0.0172 mas[1] |
Distance | 117.00 ± 0.07 ly (35.87 ± 0.02 pc) |
Absolute magnitude (MV) | +4.61[5] |
Details | |
Mass | 0.96+0.02 −0.01[6] M☉ |
Radius | 1.17±0.03[7] R☉ |
Luminosity | 1.262+0.005 −0.006[1] L☉ |
Surface gravity (log g) | 4.35+0.05 −0.08[8] cgs |
Temperature | 5,741±41[6] K |
Metallicity [Fe/H] | −0.06±0.02[9] dex |
Rotational velocity (v sin i) | 3.0±0.6[10] km/s |
Age | 8.5+2.5 −2.0[9] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Exoplanet Archive | data |
HD 20782 (HIP 15527; LTT 1582) is the primary of a wide binary system located in the southern constellation Fornax. It has an apparent magnitude of 7.38,[2] making it readily visible in binoculars but not to the naked eye. The system is located relatively close at a distance of 117 light-years based on Gaia DR3 parallax measurements,[1] but it is receding with a heliocentric radial velocity of 40.7 km/s.[4] At its current distance, HD 20782's brightness is diminished by 0.12 magnitudes due to interstellar extinction[12] and it has an absolute magnitude of +4.61.[5]
Properties
HD 20782 has a stellar classification of G1.5 V,[3] indicating that it is an ordinary G-type main-sequence star like our Sun. It has also been given a cooler class of G3 V. It has 96% the mass of the Sun[6] and 1.17 times the radius of the Sun.[7] It radiates 1.262 times the luminosity of the Sun[1] from its photosphere at an effective temperature of 5,741 K,[6] which is 35 K cooler than the Sun's temperature. When viewed in the night sky. the star has a yellow hue. HD 20782 is slightly metal deficient with an iron abundance 87.1% that of the Sun's or [Fe/H] = −0.06,[9] and it is estimated to be 8.5 billion years old,[9] which is nearly twice of the Sun's age. It spins modestly with a projected rotational velocity of 3.0 km/s.[10]
Binary System
HD 20781 is a G or K-type main-sequence star with a very large angular separation of 252 arcsec, corresponding to 9080
Planetary system
An extremely eccentric extrasolar planet was announced around HD 20782 in 2006.[16][17] In 2009 this planet's orbit was narrowed down, and it was found to have the highest eccentricity of all known exoplanets; this distinction has stood since 2012.
Companion (in order from star) |
Mass | Semimajor axis ( |
Orbital period (days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b | ≥1.49±0.11[15] MJ | 1.3649+0.0466 −0.0495[15] |
597.065±0.043[18] | 0.956±0.004[18] | — | — |
See also
References
- ^ a b c d e f g 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 Cousins, A. W. J.; Stoy, R. H. (1962). "Photoelectric magnitudes and colours of Southern stars". Royal Greenwich Observatory Bulletins. 64: 103. Bibcode:1962RGOB...64..103C. S2CID 118805499.
- ^ a b Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Bubar, E. J.; McGahee, C. E.; O'Donoghue, A. A.; Knox, E. R. (2 June 2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc--The Southern Sample". The Astronomical Journal. 132 (1): 161–170. arXiv:astro-ph/0603770. Bibcode:2006AJ....132..161G. doi:10.1086/504637. eISSN 1538-3881. ISSN 0004-6256. S2CID 250741593.
- ^ a b Valenti, Jeff A.; Fischer, Debra A. (July 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. eISSN 1538-4365. ISSN 0067-0049. S2CID 121398064.
- ^ a b Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331–346. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. eISSN 1562-6873. ISSN 1063-7737. S2CID 119257644.
- ^ a b c d Ramírez, I.; Fish, J. R.; Lambert, D. L.; Allende Prieto, C. (13 August 2012). "Lithium Abundances in nearby FGK Dwarf and Subgiant Stars: Internal Destruction, Galactic Chemical Evolution, and Exoplanets". The Astrophysical Journal. 756 (1): 46. arXiv:1207.0499. Bibcode:2012ApJ...756...46R. doi:10.1088/0004-637X/756/1/46. eISSN 1538-4357. ISSN 0004-637X. S2CID 119199829.
- ^ a b van Belle, Gerard T.; von Braun, Kaspar (March 23, 2009). "Directly Determined Linear Radii and Effective Temperatures of Exoplanet Host Stars". The Astrophysical Journal. 694 (2). American Astronomical Society: 1085–1098. arXiv:0901.1206. Bibcode:2009ApJ...694.1085V. doi:10.1088/0004-637x/694/2/1085. ISSN 0004-637X. S2CID 18370219.
- ^ Stassun, Keivan G.; et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467. eISSN 1538-3881. hdl:1721.1/124721. S2CID 166227927.
- ^ a b c d Ghezzi, L.; Cunha, K.; Smith, V. V.; de Araújo, F. X.; Schuler, S. C.; de la Reza, R. (19 August 2010). "Stellar Parameters and Metallicities of Stars Hosting Jovian and Neptunian Mass Planets: A Possible Dependence of Planetary Mass on Metallicity". The Astrophysical Journal. 720 (2): 1290–1302. arXiv:1007.2681. Bibcode:2010ApJ...720.1290G. doi:10.1088/0004-637X/720/2/1290. eISSN 1538-4357. ISSN 0004-637X.
- ^ a b Gonzalez, G.; Carlson, M. K.; Tobin, R. W. (April 11, 2010). "Parent stars of extrasolar planets - X. Lithium abundances and v sin i revisited". Monthly Notices of the Royal Astronomical Society. 403 (3). Oxford University Press (OUP): 1368–1380. arXiv:0912.1621. Bibcode:2010MNRAS.403.1368G. doi:10.1111/j.1365-2966.2009.16195.x. ISSN 0035-8711. S2CID 118520284.
- ^ "HD 20782". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-08-15.
- ^ Gontcharov, George A.; Mosenkov, Aleksandr V. (28 September 2017). "Verifying reddening and extinction for Gaia DR1 TGAS main sequence stars". Monthly Notices of the Royal Astronomical Society. 472 (4): 3805–3820. arXiv:1709.01160. Bibcode:2017MNRAS.472.3805G. doi:10.1093/mnras/stx2219. eISSN 1365-2966. ISSN 0035-8711. S2CID 118879856.
- ^ Desidera, S.; Barbieri, M. (October 24, 2006). "Properties of planets in binary systems". Astronomy & Astrophysics. 462 (1). EDP Sciences: 345–353. arXiv:astro-ph/0610623. Bibcode:2007A&A...462..345D. doi:10.1051/0004-6361:20066319. ISSN 0004-6361. S2CID 13813761.
- ^ Mayor, M.; Marmier, M.; Lovis, C.; Udry, S.; Ségransan, D.; Pepe, F.; Benz, W.; Bertaux, J. L.; Bouchy, F.; Dumusque, G.; Curto, Lo; Mordasini, C.; Queloz, D.; Santos, N. C.; et al. (2011). "The HARPS search for southern extra-solar planets XXXIV. Occurrence, mass distribution and orbital properties of super-Earths and Neptune-mass planets". arXiv:1109.2497 [astro-ph].
- ^ a b c Udry, S.; Dumusque, X.; et al. (2019). "The HARPS search for southern extra-solar planets". Astronomy & Astrophysics. 622: A37. arXiv:1705.05153. Bibcode:2019A&A...622A..37U. doi:10.1051/0004-6361/201731173. ISSN 0004-6361. S2CID 119095511.
- ^ Jones, Hugh R. A.; et al. (2006). "High-eccentricity planets from the Anglo-Australian Planet Search". Monthly Notices of the Royal Astronomical Society. 369 (1): 249–256. arXiv:astro-ph/0603335. Bibcode:2006MNRAS.369..249J. doi:10.1111/j.1365-2966.2006.10298.x.
- ^ Schneider, J. "Notes for HD 20782". Extrasolar Planets Encyclopaedia. Archived from the original on July 2, 2007.
- ^ a b Kane, Stephen R.; et al. (2016). "Evidence for Reflected Light from the Most Eccentric Exoplanet Known". The Astrophysical Journal. 821 (1). 65. arXiv:1511.08679. Bibcode:2016ApJ...821...65K. doi:10.3847/0004-637X/821/1/65.
External links
- "Planet HD 20782 b". Extrasolar Planets Encyclopaedia. Retrieved 2021-02-23.