Rho2 Cephei

Rho2 Cephei, Latinized from ρ2 Cephei, or simply ρ Cephei, is a solitary[9] star in the northern constellation of Cepheus. With an apparent visual magnitude of 5.50,[2] it is faintly visible to the naked eye, forming an optical pair with Rho1 Cephei. Based upon an annual parallax shift of 13.31 mas as seen from the Earth,[1] it is located about 245 light years from the Sun.

Rho2 Cephei
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Cepheus
Right ascension 22h 29m 52.97918s[1]
Declination +78° 49 27.4282[1]
Apparent magnitude (V) 5.50[2]
Characteristics
Spectral type A3 V[3]
U−B color index +0.07[2]
B−V color index +0.06[2]
Astrometry
Proper motion (μ) RA: +3.68[1] mas/yr
Dec.: −21.29[1] mas/yr
Parallax (π)13.31 ± 0.21[1] mas
Distance245 ± 4 ly
(75 ± 1 pc)
Absolute magnitude (MV)+1.07[4]
Details
Mass2.23±0.03[5] M
Luminosity32[4] L
Surface gravity (log g)4.2[6] cgs
Temperature8,511[5] K
Rotational velocity (v sin i)133[7] km/s
Age85[6] Myr
Other designations
 Cephei, ρ2 Cep, 29 Cephei, BD+78° 801, FK5 1593, HD 213798, HIP 111056, HR 8591, SAO 10402[8]
Database references
SIMBADdata

Rho2 Cephei is an A-type main sequence star with a stellar classification of A3 V,[3] estimated to be 85 million years old. It has a high rate of rotation, showing a projected rotational velocity of 133 km/s.[7] The effective temperature of its photosphere is 8,511 K and its bolometric luminosity, the total amount of radiation it emits at all wavelengths, is 32 L.

References

  1. van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
  2. Oja, T. (April 1983), "UBV photometry of FK4 and FK4 supplement stars", Astronomy and Astrophysics Supplement Series, 52: 131–134, Bibcode:1983A&AS...52..131O.
  3. Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819.
  4. 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.
  5. Zorec, J.; Royer, F. (January 2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
  6. Gullikson, Kevin; Kraus, Adam; Dodson-Robinson, Sarah (2016). "The Close Companion Mass-ratio Distribution of Intermediate-mass Stars". The Astronomical Journal. 152 (2): 40. arXiv:1604.06456. Bibcode:2016AJ....152...40G. doi:10.3847/0004-6256/152/2/40. S2CID 119179065.
  7. Royer, F.; et al. (February 2007), "Rotational velocities of A-type stars. III. Velocity distributions", Astronomy and Astrophysics, 463 (2): 671–682, arXiv:astro-ph/0610785, Bibcode:2007A&A...463..671R, doi:10.1051/0004-6361:20065224, S2CID 18475298.
  8. "rho Cep -- Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-05-05.
  9. 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.
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