HD 6718
HD 6718 is a solar twin star in the equatorial constellation of Cetus. It has a yellow hue but is too faint to be viewed with the naked eye, having an apparent visual magnitude of 8.45. The distance to this object, as determined from parallax measurements, is 168 light years. It is drifting away from the Sun with a radial velocity of +35 km/s.
This object is an ordinary G-type main-sequence star with a stellar classification of G5V, with the luminosity class of 'V' indicating it is generating energy through hydrogen fusion at its core. It is around six billion years old with a leisurely rotation rate, having a projected rotational velocity of 2 km/s. The level of magnetic activity in the chromosphere is considered very low and it has a near solar metallicity. Being a solar twin, has nearly the same mass and radius as the Sun. The star is radiating 1.07 times the luminosity of the Sun from its photosphere at an effective temperature of 5,728 K.
In 2009, a substellar companion (HD 6718 b) with a minimum mass of 1.56 MJ was found in orbit around the star with a period of 6.83 years. In 2020, the inclination of this object was measured, revealing its true mass to be 62.8 MJ. This makes it a brown dwarf.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 62.79+16.98 −13.80 MJ |
3.56+0.24 −0.15 |
2496±176 | 0.10+0.11 −0.04 |
1.488+0.410 −0.310° |
— |
See also
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.
- ^ 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.
- ^ Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
- ^ Høg, E.; et al. (2000). The Tycho-2 catalogue of the 2.5 million brightest stars. Vol. 355. pp. L27. Bibcode:2000A&A...355L..27H. doi:10.1888/0333750888/2862. ISBN 978-0333750889.
{{cite book}}:|journal=ignored (help) - ^ Cutri, R. M.; Skrutskie, M. F.; Van Dyk, S.; Beichman, C. A.; et al. (June 2003). "2MASS All Sky Catalog of point sources". The IRSA 2MASS All-Sky Point Source Catalog, NASA/IPAC Infrared Science Archive. Bibcode:2003tmc..book.....C.
- ^ Naef, Dominique; Mayor, Michel; Lo Curto, Gaspare; Bouchy, François; Lovis, Christophe; Moutou, Claire; Benz, Willy; Pepe, Francesco; Queloz, Didier; Santos, Nuno C.; Ségransan, Damien; Udry, Stéphane; Bonfils, Xavier; Delfosse, Xavier; Forveille, Thierry; Hébrard, Guillaume; Mordasini, Christoph; Perrier, Christian; Boisse, Isabelle; Sosnowska, Danuta (2010). "The HARPS Search for Southern Extrasolar Planets XXIII. 8 Planetary Companions to Low-activity Solar-type Stars". Astronomy and Astrophysics. 523: A15. arXiv:1008.4600. Bibcode:2010A&A...523A..15N. doi:10.1051/0004-6361/200913616. S2CID 118845989.
- ^ Bonfanti, A.; et al. (2015). "Revising the ages of planet-hosting stars". Astronomy and Astrophysics. 575. A18. arXiv:1411.4302. Bibcode:2015A&A...575A..18B. doi:10.1051/0004-6361/201424951. S2CID 54555839.
- ^ dos Santos, Leonardo A.; et al. (August 2016), "The Solar Twin Planet Search. IV. The Sun as a typical rotator and evidence for a new rotational braking law for Sun-like stars", Astronomy & Astrophysics, 592: 8, arXiv:1606.06214, Bibcode:2016A&A...592A.156D, doi:10.1051/0004-6361/201628558, S2CID 53533614, A156.
- ^ "HD 6718". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2014-09-08.
- ^ Ramírez, I.; et al. (December 2014). "The Solar Twin Planet Search. I. Fundamental parameters of the stellar sample". Astronomy & Astrophysics. 572: 19. arXiv:1408.4130. Bibcode:2014A&A...572A..48R. doi:10.1051/0004-6361/201424244. S2CID 46964342. A48.
- ^ Kiefer, F.; et al. (January 2021). "Determining the true mass of radial-velocity exoplanets with Gaia. Nine planet candidates in the brown dwarf or stellar regime and 27 confirmed planets". Astronomy & Astrophysics. 645 A7. arXiv:2009.14164. Bibcode:2021A&A...645A...7K. doi:10.1051/0004-6361/202039168. S2CID 221995447.
