7 Persei

7 Persei is a star in the constellation Perseus, located 774 light years away from the Sun.[1] While the star bears the Bayer designation Chi Persei, it is not to be confused with the entire cluster NGC 884, commonly referred to as Chi Persei. It is faintly visible to the naked eye as a dim, yellow-hued star with an apparent visual magnitude of 5.99.[2] This object is moving closer to the Earth with a heliocentric radial velocity of −12.5 km/s.[2]

This article is about the star. For the open cluster, see χ Persei.
7 Persei
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Perseus
Right ascension 02h 18m 04.58449s[1]
Declination +57° 30′ 58.7579″[1]
Apparent magnitude (V) 5.99[2]
Characteristics
Evolutionary stage horizontal branch[3]
Spectral type G7 III[4]
B−V color index 1.039±0.007[2]
Astrometry
Radial velocity (Rv)−12.5±0.3[2] km/s
Proper motion (μ) RA: −13.359[1] mas/yr
Dec.: −1.240[1] mas/yr
Parallax (π)4.2163 ± 0.0437[1] mas
Distance774 ± 8 ly
(237 ± 2 pc)
Absolute magnitude (MV)−1.22[5]
Details
Mass3.84[6] M☉
Radius24[3] R☉
Luminosity316[5] L☉
Surface gravity (log g)2.44[6] cgs
Temperature4,974[6] K
Metallicity [Fe/H]−0.11[6] dex
Rotational velocity (v sin i)11.5[7] km/s
Age191[5] Myr
Other designations
7 Per, BD+56° 486, HD 13994, HIP 10729, HR 662, SAO 23149[8]
Database references
SIMBADdata

This is an evolved giant star with a stellar classification of G7 III,[4] most likely (93% chance) on the horizontal branch.[3] At the age of 191 million years,[5] it has 3.84[6] times the mass of the Sun but has expanded to 24[3] times the Sun's radius. The star is radiating 316[5] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,974 K.[6]

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. Stock, Stephan; et al. (August 2018), "Precise radial velocities of giant stars. X. Bayesian stellar parameters and evolutionary stages for 372 giant stars from the Lick planet search", Astronomy & Astrophysics, 616: 15, arXiv:1805.04094, Bibcode:2018A&A...616A..33S, doi:10.1051/0004-6361/201833111, S2CID 119361866, A33.
  4. Currie, Thayne; et al. (2010), "The Stellar Population of h and χ Persei: Cluster Properties, Membership, and the Intrinsic Colors and Temperatures of Stars", The Astrophysical Journal Supplement, 186 (2): 191–221, arXiv:0911.5514, Bibcode:2010ApJS..186..191C, doi:10.1088/0067-0049/186/2/191, S2CID 16454332.
  5. Takeda, Yoichi; et al. (August 2008), "Stellar Parameters and Elemental Abundances of Late-G Giants", Publications of the Astronomical Society of Japan, 60 (4): 781–802, arXiv:0805.2434, Bibcode:2008PASJ...60..781T, doi:10.1093/pasj/60.4.781, S2CID 16258166.
  6. Liu, Y. J.; et al. (April 2014), "The Lithium Abundances of a Large Sample of Red Giants", The Astrophysical Journal, 785 (2): 12, arXiv:1404.1687, Bibcode:2014ApJ...785...94L, doi:10.1088/0004-637X/785/2/94, S2CID 119226316, 94.
  7. Rodrigues da Silva, R.; et al. (March 2015), "On the Nature of Rapidly Rotating Single Evolved Stars", The Astrophysical Journal, 801 (1): 6, arXiv:1503.03447, Bibcode:2015ApJ...801...54R, doi:10.1088/0004-637X/801/1/54, S2CID 119271718, 54
  8. "chi Per". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-03-24.
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