Iota Cephei

Iota Cephei
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Cepheus
Right ascension 22h 26m 42.40624s[1]
Declination +78° 47′ 09.0725″[1]
Apparent magnitude (V) 3.507[2]
Characteristics
Spectral type K0 III[3]
U−B color index +0.924[2]
B−V color index +1.053[2]
Astrometry
Radial velocity (Rv)−12.59±0.20[3] km/s
Proper motion (μ) RA: −13.33[1] mas/yr
Dec.: −36.95[1] mas/yr
Parallax (π)15.83 ± 0.23[1] mas
Distance206 ± 3 ly
(63.2 ± 0.9 pc)
Absolute magnitude (MV)0.76[3]
Details[4]
Mass2.15±0.23 M☉
Radius11.08±0.16 R☉
Luminosity57.0±0.6 L☉
Surface gravity (log g)2.69±0.06 cgs
Temperature4,768±33 K
Metallicity [Fe/H]+0.05±0.10 dex
Rotational velocity (v sin i)10[5] km/s
Age1.2±0.6 Gyr
Other designations
ι Cep, 32 Cep, BD+65° 1814, HD 216228, HIP 112724, HR 8694, SAO 20268[6]
Database references
SIMBADdata

Iota Cephei (ι Cephei, ι Cep) is a solitary[7] star in the northern constellation Cepheus. Based upon an annual parallax shift of 15.83 mas as seen from the Earth,[1] it is located about 206 light years from the Sun. The star is visible to the naked eye with an apparent visual magnitude of 3.5.[2] Due to precession of the equinoxes, it will become the north pole star some time around 5200 CE.

This is a K-type giant star with a stellar classification of K0 III.[3] It is currently at an evolutionary stage known as a red clump, indicating that it is generating energy through the fusion of helium at its core.[8] This star has 11 times the Sun's radius and about 2.15 times the mass of the Sun. It is emitting 57 times as much luminosity as the Sun, which is being radiated from its photosphere at an effective temperature of 4,768 K.[4]

References

  1. 1 2 3 4 5 6 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, Bibcode:2007A&A...474..653V, arXiv:0708.1752 Freely accessible, doi:10.1051/0004-6361:20078357.
  2. 1 2 3 4 Jennens, P. A.; Helfer, H. L. (September 1975), "A new photometric metal abundance and luminosity calibration for field G and K giants", Monthly Notices of the Royal Astronomical Society, 172: 667–679, Bibcode:1975MNRAS.172..667J, doi:10.1093/mnras/172.3.667.
  3. 1 2 3 4 Hekker, S.; et al. (August 2006), "Precise radial velocities of giant stars. I. Stable stars", Astronomy and Astrophysics, 454 (3): 943–949, Bibcode:2006A&A...454..943H, arXiv:astro-ph/0604502 Freely accessible, doi:10.1051/0004-6361:20064946.
  4. 1 2 Reffert, Sabine; et al. (2015), "Precise radial velocities of giant stars. VII. Occurrence rate of giant extrasolar planets as a function of mass and metallicity", Astronomy & Astrophysics, 574: A116, Bibcode:2015A&A...574A.116R, arXiv:1412.4634 Freely accessible, doi:10.1051/0004-6361/201322360.
  5. ↑ Bernacca, P. L.; Perinotto, M. (1970), "A catalogue of stellar rotational velocities", Contributi Osservatorio Astronomico di Padova in Asiago, 239 (1), Bibcode:1970CoAsi.239....1B.
  6. ↑ "iot Cep -- Variable Star", SIMBAD Astronomical Database, Centre de Données astronomiques de Strasbourg, retrieved 2017-05-06.
  7. ↑ 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, Bibcode:2008MNRAS.389..869E, arXiv:0806.2878 Freely accessible, doi:10.1111/j.1365-2966.2008.13596.x.
  8. ↑ Tautvaišienė, G.; et al. (December 2010), "C, N and O abundances in red clump stars of the Milky Way", Monthly Notices of the Royal Astronomical Society, 409 (3): 1213–1219, Bibcode:2010MNRAS.409.1213T, arXiv:1007.4064 Freely accessible, doi:10.1111/j.1365-2966.2010.17381.x.
Preceded by
Gamma Cephei		 Pole Star
5200–6800 		Succeeded by
Alderamin

Coordinates: 22h 49m 40.91s, +66° 12′ 2.6″

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