HD 208487

HD 208487 is a 7th magnitude G-type main sequence star located approximately 144 light-years away in the constellation of Grus. It has the same spectral type as our sun, G2V. However, it is probably slightly less massive and more luminous, indicating that it is slightly older. As of 2008, there is one known extrasolar planet confirmed to be orbiting the star.

HD 208487
Observation data
Epoch J2000      Equinox J2000
Constellation Grus
Right ascension  21h 57m 19.84754s[1]
Declination −37° 45′ 49.0480″[1]
Apparent magnitude (V) 7.47[2]
Characteristics
Spectral type G2V[3]
Astrometry
Radial velocity (Rv)5.575 ± 0.0004[4] km/s
Proper motion (μ) RA: 101.138[1] mas/yr
Dec.: −118.666[1] mas/yr
Parallax (π)22.1214 ± 0.0773[1] mas
Distance147.4 ± 0.5 ly
(45.2 ± 0.2 pc)
Absolute magnitude (MV)4.26[3]
Absolute bolometric
magnitude (Mbol)		4.06[3]
Details[3]
Mass0.95 􏰅± 0.05 M☉
Temperature5929 􏰅± 20 K
Age6.3–10 Gyr
Other designations
Itonda, CD−38° 14804, HIP 108375, SAO 213432[5]
Database references
SIMBADdata

The star HD 208487 is named Itonda. The name was selected in the NameExoWorlds campaign by Gabon, during the 100th anniversary of the IAU. Itonda, in the Myene tongue, corresponds to all that is beautiful.[6][7]

Planetary system

There is one known planet orbiting the star HD 208487, which is designated HD 208487 b.[3] It has a mass at least half that of Jupiter and is located in an eccentric 130-day orbit.

The discovery of a second planet in the system was announced on September 13, 2005, by P.C. Gregory. The discovery was made using Bayesian analysis of the radial velocity dataset to determine the planetary parameters.[8] However, further analysis revealed that an alternative 2-planet solution for the HD 208487 system was possible, with a planet in a 28-day orbit instead of the 908-day orbit postulated, and it was concluded that activity on the star is more likely to be responsible for the residuals to the one-planet solution than the presence of a second planet.[9]

The HD 208487 planetary system
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b >0.520 ± 0.082 MJ 0.51 ± 0.02 130.08 ± 0.51 0.24 ± 0.16 — —

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.
  2. Høg, E.; et al. (2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H.
  3. Tinney, C. G.; et al. (2005). "Three Low-Mass Planets from the Anglo-Australian Planet Search". The Astrophysical Journal. 623 (2): 1171–1179. Bibcode:2005ApJ...623.1171T. CiteSeerX 10.1.1.491.2941. doi:10.1086/428661.
  4. Soubiran, C.; Jasniewicz, G.; Chemin, L.; Zurbach, C.; Brouillet, N.; Panuzzo, P.; Sartoretti, P.; Katz, D.; Le Campion, J. -F.; Marchal, O.; Hestroffer, D.; Thévenin, F.; Crifo, F.; Udry, S.; Cropper, M.; Seabroke, G.; Viala, Y.; Benson, K.; Blomme, R.; Jean-Antoine, A.; Huckle, H.; Smith, M.; Baker, S. G.; Damerdji, Y.; Dolding, C.; Frémat, Y.; Gosset, E.; Guerrier, A.; Guy, L. P.; et al. (2018). "Gaia Data Release 2. The catalogue of radial velocity standard stars". Astronomy and Astrophysics. 616: A7. arXiv:1804.09370. Bibcode:2018A&A...616A...7S. doi:10.1051/0004-6361/201832795.
  5. "HD 208487". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2020-05-06.
  6. "Approved names". NameExoworlds. Retrieved 2020-01-02.
  7. "International Astronomical Union | IAU". www.iau.org. Retrieved 2020-01-02.
  8. Gregory, P.C. (2007). "A Bayesian Kepler periodogram detects a second planet in HD 208487". MNRAS. 374 (4): 1321–1333. arXiv:astro-ph/0609229. Bibcode:2007MNRAS.374.1321G. doi:10.1111/j.1365-2966.2006.11240.x.
  9. Wright, J.T.; et al. (2007). "Four New Exoplanets and Hints of Additional Substellar Companions to Exoplanet Host Stars". The Astrophysical Journal. 657 (1): 533–545. arXiv:astro-ph/0611658. Bibcode:2007ApJ...657..533W. doi:10.1086/510553.


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