HD 20868

HD 20868 is a star in the southern constellation Fornax. With an apparent visual magnitude of 9.92,[2] it is much too dim to be visible to the naked eye. Parallax measurements give a distance estimate of 156 light years from the Sun. It is drifting further away with a radial velocity of +46.2 km/s,[1] having come to within about 124 ly around 312,000 years ago.[2]

HD 20868
Observation data
Epoch J2000      Equinox J2000
Constellation Fornax
Right ascension 03h 20m 42.69389s[1]
Declination −33° 43′ 48.3739″[1]
Apparent magnitude (V) 9.92[2]
Characteristics
Spectral type K3/4 III/V[3]
Apparent magnitude (B) 11.07[4]
Apparent magnitude (J) 8.138±0.032[5]
Apparent magnitude (H) 7.641±0.031[5]
Apparent magnitude (K) 7.543±0.015[5]
B−V color index 1.037±0.005[2]
Astrometry
Radial velocity (Rv)46.207±0.0011[1] km/s
Proper motion (μ) RA: 292.467±0.035[1] mas/yr
Dec.: 96.138±0.058[1] mas/yr
Parallax (π)20.9257 ± 0.0304[1] mas
Distance155.9 ± 0.2 ly
(47.79 ± 0.07 pc)
Absolute magnitude (MV)6.61[2]
Details[6]
Mass0.76±0.02 M☉
Radius0.73±0.01 R☉
Luminosity0.255±0.002 L☉
Surface gravity (log g)4.59±0.02 cgs
Temperature4,811±14 K
Metallicity [Fe/H]0.04±0.1 dex
Age8.4±3.7 Gyr
Other designations
CD−34°1218, HD 20868, HIP 15578, PPM 278952, LTT 1589, 2MASS J03204266-3343484[7]
Database references
SIMBADdata
Exoplanet Archivedata
Extrasolar Planets
Encyclopaedia		data

This object is a K-type star with a stellar classification of K3/4 III/V.[3] It is around eight billion years old with 76% of the mass of the Sun and 73% of the Sun's radius. It is radiating 25.5% of the luminosity of the Sun from its photosphere at an effective temperature of 4,811 K. The metallicity of the star is near solar, meaning it has about the same abundance of iron as in the Sun.[6]

The star HD 20868 is named Intan. The name was selected in the NameExoWorlds campaign by Malaysia, during the 100th anniversary of the IAU. Intan means diamond in the Malay language.[8][9]

Planetary system

In October 2008 a planet, HD 20868 b, was discovered. This object was detected using the radial velocity method by search programs conducted using the HARPS spectrograph. The orbital solution indicates this is a giant planet in a highly elliptical orbit around the host star.[10]

The HD 20868 planetary system[10]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b ≥1.99±0.05 MJ 0.947±0.012 380.85±0.09 0.75±0.002 — —

See also
  • List of extrasolar planets

References
  1. 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.
  2. 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.
  3. Houk, Nancy (1979). Michigan catalogue of two-dimensional spectral types for the HD stars. 3. Ann Arbor, Michigan: Dept. of Astronomy, University of Michigan. Bibcode:1982mcts.book.....H.
  4. Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27. Bibcode:2000A&A...355L..27H.
  5. Cutri, R. M.; et al. (June 2003). 2MASS All Sky Catalog of point sources. NASA/IPAC. Bibcode:2003tmc..book.....C.
  6. 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.
  7. "HD 20868". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-12-23.
  8. "Approved names". NameExoworlds. Retrieved 2020-01-02.
  9. "International Astronomical Union | IAU". www.iau.org. Retrieved 2020-01-02.
  10. Moutou, C.; et al. (2009). "The HARPS search for southern extra-solar planets XVII. Six long-period giant planets around BD -17 0063, HD 20868, HD 73267, HD 131664, HD 145377, HD 153950". Astronomy and Astrophysics. 496 (2): 513–519. arXiv:0810.4662. Bibcode:2009A&A...496..513M. doi:10.1051/0004-6361:200810941.

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