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81 Ceti
View on Wikipedia| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cetus |
| Right ascension | 02h 37m 41.80208s[1] |
| Declination | −03° 23′ 46.2259″[1] |
| Apparent magnitude (V) | 5.65[2] |
| Characteristics | |
| Evolutionary stage | red clump[3] |
| Spectral type | K0III[4] or G5III[5] |
| B−V color index | 1.021±0.001[2] |
| Astrometry | |
| Radial velocity (Rv) | +9.14±0.12[1] km/s |
| Proper motion (μ) | RA: 41.765 mas/yr[1] Dec.: −43.379 mas/yr[1] |
| Parallax (π) | 9.5199±0.0756 mas[1] |
| Distance | 343 ± 3 ly (105.0 ± 0.8 pc) |
| Absolute magnitude (MV) | 0.82[2] |
| Details[6] | |
| Mass | 1.6±0.2 M☉ |
| Radius | 11.1±0.3 R☉ |
| Luminosity | 60.0±0.8 L☉ |
| Surface gravity (log g) | 2.5±0.1 cgs |
| Temperature | 4,825±41 K |
| Metallicity [Fe/H] | 0.00±0.04[7] dex |
| Rotational velocity (v sin i) | 1.20±0.47[7] km/s |
| Age | 2.5±0.9 Gyr |
| Other designations | |
| 81 Cet, BD−04°436, GC 3158, HD 16400, HIP 12247, HR 771, SAO 130026 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
81 Ceti is a star located approximately 343 light-years away from the Sun in the equatorial constellation of Cetus. 81 Ceti is the Flamsteed designation for this object. It is visible to the naked eye as a dim, yellow-hued point of light with an apparent visual magnitude of 5.65.[2] The star is drifting further away from the Earth with a heliocentric radial velocity of +9 km/s.[2]
This is an aging K-type giant star with a stellar classification of K0III,[4] having exhausted the supply of hydrogen at its core and expanded to 11[6] times the Sun's radius. It is a red clump giant,[3] which indicates it is on the horizontal branch and is generating energy from core helium fusion. The star is now 2.5 billion years old with 1.6 times the mass of the Sun.[6] It is radiating 60 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of 4,825 K.[6]
Planetary system
[edit]In July 2008, the planet 81 Ceti b was announced by Sato and collaborators, along with 14 Andromedae b and 6 Lyncis b. The planet was found to be a super-Jupiter, with 5.3 times the mass of Jupiter. It takes 953 days for it to complete its orbit around the star.[5] The planetary parameters were updated in 2023.[8]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥3.307+0.078 −0.067 MJ |
2.104±0.003 | 1005.57+1.84 −1.94 |
0.037+0.015 −0.025 |
— | — |
See also
[edit]References
[edit]- ^ a b c d e Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c d e 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.
- ^ a b Mishenina, T. V.; et al. (September 2006), "Elemental abundances in the atmosphere of clump giants", Astronomy and Astrophysics, 456 (3): 1109–1120, arXiv:astro-ph/0605615, Bibcode:2006A&A...456.1109M, doi:10.1051/0004-6361:20065141, S2CID 18764566
- ^ a b Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
- ^ a b Sato, Bun'ei; et al. (2008). "Planetary Companions to Evolved Intermediate-Mass Stars: 14 Andromedae, 81 Ceti, 6 Lyncis, and HD167042". Publications of the Astronomical Society of Japan. 60 (6): 1317–1326. arXiv:0807.0268. Bibcode:2008PASJ...60.1317S. doi:10.1093/pasj/60.6.1317. S2CID 67841762.
- ^ a b c d 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.
- ^ a b Jofré, E.; et al. (2015). "Stellar parameters and chemical abundances of 223 evolved stars with and without planets". Astronomy & Astrophysics. 574: A50. arXiv:1410.6422. Bibcode:2015A&A...574A..50J. doi:10.1051/0004-6361/201424474. S2CID 53666931.
- ^ a b Teng, Huan-Yu; Sato, Bun'ei; et al. (August 2023). "Revisiting planetary systems in the Okayama Planet Search Program: A new long-period planet, RV astrometry joint analysis, and a multiplicity-metallicity trend around evolved stars". Publications of the Astronomical Society of Japan. 75 (6): 1030–1071. arXiv:2308.05343. Bibcode:2023PASJ...75.1030T. doi:10.1093/pasj/psad056.
External links
[edit]- Jean Schneider (2011). "Notes for star 81 Cet". Extrasolar Planets Encyclopaedia. Archived from the original on August 3, 2008. Retrieved 12 October 2011.
