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 |
| Distance | 206 ± 3 ly (63.2 ± 0.9 pc) |
| Absolute magnitude (MV) | 0.76[3] |
| Details[4] | |
| Mass | 2.15±0.23 M☉ |
| Radius | 11.08±0.16 R☉ |
| Luminosity | 57.0±0.6 L☉ |
| Surface gravity (log g) | 2.69±0.06 cgs |
| Temperature | 4,768±33 K |
| Metallicity [Fe/H] | +0.05±0.10 dex |
| Rotational velocity (v sin i) | 10[5] km/s |
| Age | 1.2±0.6 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
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]
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]
Pole Star
Iota Cephei is a visible star located within 5° of the precessional path traced across the celestial sphere by the Earth's North pole. During the same period Alfirk will also be within 5° of the precessional path, on the other side so that both are in contention as pole stars, a title currently held by unambiguously by Polaris.
| Preceded by | Pole Star | Succeeded by |
|---|---|---|
| Errai | 5200AD to 7500AD with Alfirk |
Alderamin |
References
- 1 2 3 4 5 6 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.
- 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.
- 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, arXiv:astro-ph/0604502, Bibcode:2006A&A...454..943H, doi:10.1051/0004-6361:20064946.
- 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, arXiv:1412.4634, Bibcode:2015A&A...574A.116R, doi:10.1051/0004-6361/201322360.
- ↑ 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.
- ↑ "iot Cep". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-05-06.
- ↑ 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.
- ↑ 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, arXiv:1007.4064, Bibcode:2010MNRAS.409.1213T, doi:10.1111/j.1365-2966.2010.17381.x.
