HD 108863

HD 108863
Observation data
Epoch J2000      Equinox J2000
Constellation Coma Berenices
Right ascension 12h 30m 19.9101s[1]
Declination +21° 56′ 53.6794″[1]
Apparent magnitude (V) 7.71[2]
Characteristics
Evolutionary stage subgiant
Spectral type K0III-IV[3]
B−V color index 0.99[4]
Astrometry
Radial velocity (Rv)−27.832 km/s
Proper motion (μ) RA: −75.501 mas/yr
Dec.: −33.669 mas/yr
Parallax (π)6.0417 ± 0.0485 mas[5]
Distance540 ± 4 ly
(166 ± 1 pc)
Orbit[6]
PrimaryHD 108863
CompanionHD 108863 B
Semi-major axis (a)0.115"
(16.065 AU)
Details[2]
Mass1.59 M☉
Radius5.74 R☉
Surface gravity (log g)3.07 cgs
Temperature4,878 K
Metallicity0.02[7]
Rotational velocity (v sin i)1.6±0.6[7] km/s
Age1.8±0.4[8] Gyr
Other designations
BD+22 2478, Gaia DR2 3952692457305436800, HD 108863, HIP 61020, TYC 1447-2345-1, 2MASS J12301991+2156537[1]
Database references
SIMBADdata

HD 108863 is a subgiant star, the primary of a binary star system 540 light-years away, belonging to spectral class K0. Its age is younger than the Sun's at 1.8±0.4 billion years.[8] The primary star is slightly enriched in heavy elements, having 115% of solar abundance.[7] The primary star does not have detectable flare activity.[9]

In 2014, a poorly characterized co-moving stellar companion HD 108863 B, likely a main sequence star of spectral class between F6 and G4, was discovered at a projected separation of 16.065 AU.[6]

Planetary system

In 2011 one superjovian planet, HD 108863 b, on a nearly circular orbit around star HD 108863 was discovered utilizing the radial velocity method.[4] The planet does not transit its host star.[2]

The HD 108863 planetary system[10]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
HD 108863 b ≥2.6±0.2 MJ 1.40±0.03 443.4±4.2 <0.1 — —

References

  1. ^ a b c "HD 108863". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 20 October 2020.
  2. ^ a b c Luhn, Jacob K.; Bastien, Fabienne A.; Wright, Jason T.; Johnson, John A.; Howard, Andrew W.; Isaacson, Howard (2018), "Retired A Stars and Their Companions VIII: 15 New Planetary Signals Around Subgiants and Transit Parameters for California Planet Search Planets with Subgiant Hosts", The Astronomical Journal, 157 (4): 149, arXiv:1811.03043, Bibcode:2019AJ....157..149L, doi:10.3847/1538-3881/aaf5d0, S2CID 102486961
  3. ^ Yoss, K. M.; Griffin, R. F. (September 1997), "Radial Velocities and DDO, BV Photometry of Henry Draper G5-M Stars Near the North Galactic Pole", Journal of Astrophysics and Astronomy, 18 (2–3): 161, Bibcode:1997JApA...18..161Y, doi:10.1007/BF02714877, S2CID 123221180.
  4. ^ a b John Asher Johnson; Clanton, Christian; Howard, Andrew W.; Bowler, Brendan P.; Henry, Gregory W.; Marcy, Geoffrey W.; Crepp, Justin R.; Endl, Michael; Cochran, William D.; MacQueen, Phillip J.; Wright, Jason T.; Isaacson, Howard (2011), "Retired a Stars and Their Companions. Vii. 18 New Jovian Planets", The Astrophysical Journal Supplement Series, 197 (2): 26, arXiv:1108.4205, Bibcode:2011ApJS..197...26J, doi:10.1088/0067-0049/197/2/26, S2CID 15088371
  5. ^ 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.
  6. ^ a b Mugrauer, M.; Ginski, C.; Seeliger, M. (2014). "New wide stellar companions of exoplanet host stars". Monthly Notices of the Royal Astronomical Society. 439 (1): 1063–1070. Bibcode:2014MNRAS.439.1063M. doi:10.1093/mnras/stu044.
  7. ^ a b c Ghezzi, Luan; Montet, Benjamin T.; Johnson, John Asher (2018), "Retired a Stars Revisited: An Updated Giant Planet Occurrence Rate as a Function of Stellar Metallicity and Mass", The Astrophysical Journal, 860 (2): 109, arXiv:1804.09082, Bibcode:2018ApJ...860..109G, doi:10.3847/1538-4357/aac37c, S2CID 118969017
  8. ^ a b Bonsor, Amy; Kennedy, Grant M.; Wyatt, Mark C.; Johnson, John A.; Sibthorpe, Bruce (2013), "Herschel Observations of Debris Discs Orbiting Planet-hosting Subgiants", Monthly Notices of the Royal Astronomical Society, 437 (4): 3288–3297, arXiv:1311.2947, doi:10.1093/mnras/stt2128, S2CID 53586078
  9. ^ Shkolnik, Evgenya L. (2013), "An Ultraviolet Investigation of Activity on Exoplanet Host Stars", The Astrophysical Journal, 766 (1): 9, arXiv:1301.6192, Bibcode:2013ApJ...766....9S, doi:10.1088/0004-637X/766/1/9, S2CID 118415788
  10. ^ Planet HD 108863 b on exoplanet.eu