79 Ceti

79 Ceti, also known as HD 16141, is a binary star system located 123[1] light-years from the Sun in the southern constellation of Cetus. It has an apparent visual magnitude of +6.83,[2] which puts it below the normal limit for visibility with the average naked eye. The star is drifting closer to the Earth with a heliocentric radial velocity of −51 km/s.[2]

79 Ceti
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cetus
Right ascension 02h 35m 19.9293s[1]
Declination −03° 33′ 38.1707″[1]
Apparent magnitude (V) +6.83[2]
Characteristics
Spectral type G2V+M[3][4] or G8IV[5]
B−V color index 0.670±0.004[2]
Variable type none
Astrometry
Radial velocity (Rv)−50.93±0.09[2] km/s
Proper motion (μ) RA: −155.58[1] mas/yr
Dec.: −437.99[1] mas/yr
Parallax (π)26.4360 ± 0.0580[1] mas
Distance123.4 ± 0.3 ly
(37.83 ± 0.08 pc)
Absolute magnitude (MV)+3.88[2]
Details[6]
79 Ceti A
Mass1.01 M☉
Radius1.48[7] R☉
Luminosity1.99±0.04 L☉
Surface gravity (log g)4.19±0.02 cgs
Temperature5,806±17 K
Metallicity [Fe/H]+0.16±0.01[6] dex
Age6.0[8] or 9.4±0.8[2] Gyr
79 Ceti B
Mass0.286[4] M☉
Other designations
79 Cet, BD−04°426, FK5 4237, Gaia DR2 2495335115182966016, GJ 9085, HD 16141, HIP 12048, SAO 129992, WDS J02353-0334A, 2MASS J02351994-0333376[9]
Database references
SIMBADdata

Harlan (1974) assigned this star a stellar classification of G2V,[3] matching an ordinary G-type main-sequence star that is undergoing core hydrogen fusion. However, Houk and Swift (1999) found a class of G8IV,[5] which suggests it has exhausted the supply of hydrogen at its core and begun to evolve off the main sequence. Eventually the outer layers of the star will expand and cool and the star will become a red giant. Estimates of the star's age range from 6.0[8] to 9.4 billion years old. It has an estimated 1.06 times the mass of the Sun and 1.48[7] times the Sun's radius. The star is radiating twice[6] luminosity of the Sun from its photosphere at an effective temperature of 5,806 K.[6] The discrepancy was later been found due to an additional red dwarf star in system at projected separation 220 AUs.[4]

Planetary system

On March 29, 2000, a planet orbiting primary star was announced, it was discovered using the radial velocity method.[10] This object has a minimum 0.26 times the mass of Jupiter and is orbiting its host star every 75.5 days.[11]

The 79 Ceti planetary system[12]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
b ≥0.260 ± 0.028 MJ 0.363 ± 0.021 75.523 ± 0.055 0.252 ± 0.052 — —

See also

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. Harlan, E. A. (June 1974). "MK classification for F- and G-type stars. III". Astronomical Journal. 79: 682–686. Bibcode:1974AJ.....79..682H. doi:10.1086/111597.
  4. Quarles, Billy; Li, Gongjie; Kostov, Veselin; Haghighipour, Nader (2020), "Orbital Stability of Circumstellar Planets in Binary Systems", The Astronomical Journal, 159 (3): 80, arXiv:1912.11019, doi:10.3847/1538-3881/ab64fa, S2CID 209444271
  5. Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
  6. S. G., Sousa; et al. (August 2008). "Spectroscopic parameters for 451 stars in the HARPS GTO planet search program. Stellar [Fe/H] and the frequency of exo-Neptunes". Astronomy and Astrophysics. 487 (1): 373–381. arXiv:0805.4826. Bibcode:2008A&A...487..373S. doi:10.1051/0004-6361:200809698. S2CID 18173201.
  7. Stassun, Keivan G.; et al. (March 2017). "Accurate Empirical Radii and Masses of Planets and Their Host Stars with Gaia Parallaxes". The Astronomical Journal. 153 (3): 20. arXiv:1609.04389. Bibcode:2017AJ....153..136S. doi:10.3847/1538-3881/aa5df3. S2CID 119219062. 136.
  8. Sousa, S. G.; et al. (March 2010). "Higher depletion of lithium in planet host stars: no age and mass effect". Astronomy and Astrophysics. 512: L5. arXiv:1003.0405. Bibcode:2010A&A...512L...5S. doi:10.1051/0004-6361/201014125. S2CID 118646949.
  9. "79 Cet". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 19 August 2017.
  10. "Keck astronomers discover planets smaller than saturn" (Press release). Kamuela, Hawaii: W. M. Keck Observatory. March 29, 2000. Retrieved August 13, 2019.
  11. Marcy, Geoffrey W.; et al. (2000). "Sub-Saturn Planetary Candidates of HD 16141 and HD 46375". The Astrophysical Journal Letters. 536 (1): L43–L46. arXiv:astro-ph/0004326. Bibcode:2000ApJ...536L..43M. doi:10.1086/312723. PMID 10849416.
  12. Butler, J. T.; et al. (2006). "Catalog of Nearby Exoplanets". The Astrophysical Journal. 646 (1): 505–522. arXiv:astro-ph/0607493. Bibcode:2006ApJ...646..505B. doi:10.1086/504701. S2CID 119067572.

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