| 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] |
| Distance | 540 ± 4 ly (166 ± 1 pc) |
| Orbit[6] | |
| Primary | HD 108863 |
| Companion | HD 108863 B |
| Semi-major axis (a) | 0.115" (16.065 AU) |
| Details[2] | |
| Mass | 1.59 M☉ |
| Radius | 5.74 R☉ |
| Surface gravity (log g) | 3.07 cgs |
| Temperature | 4,878 K |
| Metallicity | 0.02[7] |
| Rotational velocity (v sin i) | 1.6±0.6[7] km/s |
| Age | 1.8±0.4[8] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
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]
| 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 2 3 "HD 108863". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 20 October 2020.
- 1 2 3 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
- ↑ 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.
- 1 2 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
- ↑ 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.
- 1 2 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.
- 1 2 3 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
- 1 2 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
- ↑ 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
- ↑ Planet HD 108863 b on exoplanet.eu
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