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24 Cephei

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24 Cephei
Location of 24 Cephei (circled in red)
Observation data
Epoch J2000      Equinox ICRS
Constellation Cepheus
Right ascension 22h 09m 48.43066s[1]
Declination +72° 20 28.3397[1]
Apparent magnitude (V) 4.79[2]
Characteristics
Evolutionary stage red giant branch[1]
Spectral type G7 II-III[3]
B−V color index 0.898[4]
Astrometry
Radial velocity (Rv)−16.58[4] km/s
Proper motion (μ) RA: +33.041[1] mas/yr
Dec.: +2.809[1] mas/yr
Parallax (π)8.2802±0.0916 mas[1]
Distance394 ± 4 ly
(121 ± 1 pc)
Absolute magnitude (MV)−0.519[4]
Details
Mass3.50[5] M
Radius16.8[6] R
Luminosity209[5] L
Surface gravity (log g)2.31±0.33[7] cgs
Temperature5,023±54[7] K
Metallicity [Fe/H]−0.16±0.11[7] dex
Rotational velocity (v sin i)6.5[8] km/s
Age234[5] Myr
Other designations
24 Cep, BD+71°1111, FK5 837, HD 210807, HIP 109400, HR 8468, SAO 10265[9]
Database references
SIMBADdata

24 Cephei is a single,[10] yellow-hued star in the northern circumpolar constellation of Cepheus. With an apparent visual magnitude of 4.79,[2] it is faintly visible to the naked eye. The distance to this star, based upon an annual parallax shift of 8.28 mas,[1] is around 394 light years. It is moving closer with a heliocentric radial velocity of −17 km/s.[4]

Keenan and McNeil (1989) listed a stellar classification of G7 II-III[3] for 24 Cep, matching the spectrum of an evolved G-type star with blended features of a bright giant and a giant star. Older sources list a class of G8 III,[11] which would suggest an ordinary giant star. At the age of 234 million years,[5] it has an estimated 3.5 times the mass of the Sun[5] and has expanded to about 17 times the Sun's radius.[6] The star is radiating 199 times the Sun's luminosity[2] from its enlarged photosphere at an effective temperature of 5,023 K.[7] These coordinates are a source of X-ray emission.[12]

References

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  1. 1 2 3 4 5 6 7 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.
  2. 1 2 3 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. 1 2 Keenan, Philip C.; McNeil, Raymond C. (1989), "The Perkins catalog of revised MK types for the cooler stars", The Astrophysical Journal Supplement Series, 71: 245, Bibcode:1989ApJS...71..245K, doi:10.1086/191373.
  4. 1 2 3 4 Soubiran, C.; et al. (2008), "Vertical distribution of Galactic disk stars. IV. AMR and AVR from clump giants", Astronomy and Astrophysics, 480 (1): 91–101, arXiv:0712.1370, Bibcode:2008A&A...480...91S, doi:10.1051/0004-6361:20078788, S2CID 16602121.
  5. 1 2 3 4 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.
  6. 1 2 Fetherolf, Tara; Pepper, Joshua; Simpson, Emilie; Kane, Stephen R.; Močnik, Teo; English, John Edward; Antoci, Victoria; Huber, Daniel; Jenkins, Jon M.; Stassun, Keivan; Twicken, Joseph D.; Vanderspek, Roland; Winn, Joshua N. (2023). "Variability Catalog of Stars Observed during the TESS Prime Mission". The Astrophysical Journal Supplement Series. 268 (1): 4. arXiv:2208.11721. Bibcode:2023ApJS..268....4F. doi:10.3847/1538-4365/acdee5.
  7. 1 2 3 4 Koleva, M.; Vazdekis, A. (February 2012), "Stellar population models in the UV. I. Characterisation of the New Generation Stellar Library", Astronomy & Astrophysics, 538: A143, arXiv:1111.5449, Bibcode:2012A&A...538A.143K, doi:10.1051/0004-6361/201118065, S2CID 53999614.
  8. Lèbre, A.; et al. (May 2006), "Lithium abundances and rotational behavior for bright giant stars", Astronomy and Astrophysics, 450 (3): 1173–1179, Bibcode:2006A&A...450.1173L, doi:10.1051/0004-6361:20053485.
  9. "24 Cep". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-07-06.
  10. Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
  11. Roman, Nancy G. (1952), "The Spectra of the Bright Stars of Types F5-K5", Astrophysical Journal, 116: 122–143, Bibcode:1952ApJ...116..122R, doi:10.1086/145598.
  12. Haakonsen, Christian Bernt; Rutledge, Robert E. (September 2009), "XID II: Statistical Cross-Association of ROSAT Bright Source Catalog X-ray Sources with 2MASS Point Source Catalog Near-Infrared Sources", The Astrophysical Journal Supplement, 184 (1): 138–151, arXiv:0910.3229, Bibcode:2009ApJS..184..138H, doi:10.1088/0067-0049/184/1/138, S2CID 119267456.