Astronomy:Omicron Cephei
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Short description: Star in the constellation Cepheus
| Observation data {{#ifeq:J2000.0|J2000.0 (ICRS)|Epoch J2000.0 Equinox J2000.0 (ICRS)| [[History:Epoch|Epoch J2000.0]] [[Astronomy:Equinox (celestial coordinates)|Equinox J2000.0}} | |
|---|---|
| Constellation | Cepheus |
| ο Cep A | |
| Right ascension | 23h 18m 37.493s |
| Declination | +68° -6′ 41.20″[1] |
| Apparent magnitude (V) | 4.86[2] |
| ο Cep B | |
| Right ascension | 23h 18m 37.115s |
| Declination | +68° 06′ 38.65″[3] |
| Apparent magnitude (V) | 7.13[2] |
| Characteristics | |
| U−B color index | +0.49[2] |
| B−V color index | +0.84[2] |
| R−I color index | +0.45[2] |
| ο Cep A | |
| Spectral type | G8III[4] |
| ο Cep B | |
| Spectral type | F6V[2] |
| Astrometry | |
| ο Cep A | |
| Proper motion (μ) | RA: 54.88[1] mas/yr Dec.: 10.91[1] mas/yr |
| Parallax (π) | 15.48 ± 0.55[5] mas |
| Distance | 211 ± 7 ly (65 ± 2 pc) |
| Absolute magnitude (MV) | 0.78[6] |
| ο Cep B | |
| Proper motion (μ) | RA: 45.70[3] mas/yr Dec.: 13.19[3] mas/yr |
| Orbit[4] | |
| Period (P) | 1505±40 y |
| Semi-major axis (a) | 3.13±0.12 ″ |
| Eccentricity (e) | 0.439±0.020 |
| Inclination (i) | 16.0±4.0° |
| Longitude of the node (Ω) | 4.5±4.5° |
| Periastron epoch (T) | B1692 ± 20 |
| Argument of periastron (ω) (secondary) | 93.0±20.0° |
| Details | |
| ο Cep A | |
| Mass | 2.35 ± 0.15[4] M☉ |
| Luminosity | 51[6] L☉ |
| Metallicity [Fe/H] | 0.05±0.02[6] dex |
| ο Cep B | |
| Mass | 1.29[4] M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
Omicron Cephei, Latinized from ο Cephei, is a binary star in the constellation of Cepheus.[5] It consists of a less massive F-type main sequence star in orbit with a more massive G-type giant star.[4] The overall apparent visual magnitude of the system is 4.75.[2]
The pair was first determined to be binary by F. G. W. Struve in 1832. Since then, the secondary has been seen to revolve approximately 45 degrees around the primary. A number of orbits have been computed, the most recent giving a period of approximately 1500 years.[4]
Visual companion
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Cepheus |
| Right ascension | 23h 18m 37.5s[8] |
| Declination | +68° 07′ 26″[8] |
| Apparent magnitude (V) | 12.8[8] |
| Position (relative to A) | |
| Epoch of observation | 1912 |
| Angular distance | 45.6″ [7] |
| Position angle | 4° [7] |
| Other designations | |
| Database references | |
| SIMBAD | data |
There is a visual companion, CCDM J23186+6807C, to the binary star. It has an approximate apparent visual magnitude of 12.8 and is located approximately 45 arcseconds away from it.[7][8]
References
- ↑ 1.0 1.1 1.2 Component 1, HIP 115088, database entry, The Hipparcos and Tycho Catalogues, 1997, CDS ID I/239.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 HR 8872, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line November 24, 2008.
- ↑ 3.0 3.1 3.2 Component 2, HIP 115088, database entry, The Hipparcos and Tycho Catalogues, 1997, CDS ID I/239.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Docobo, Jos A. (2003). "Orbit and System Mass for the Visual Binary WDS 23186+6807AB". The Astronomical Journal 126 (3): 1522–1525. doi:10.1086/377319. Bibcode: 2003AJ....126.1522D..
- ↑ 5.0 5.1 5.2 "* omi Cep". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+omi+Cep.
- ↑ 6.0 6.1 6.2 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 7.0 7.1 7.2 7.3 7.4 Entry 23186+6807, The Washington Double Star Catalog, United States Naval Observatory. Accessed on line November 24, 2008.
- ↑ 8.0 8.1 8.2 8.3 8.4 "UCAC3 317-95637". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=UCAC3+317-95637.
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