Omicron Cephei
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| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | ||
| Constellation | Cepheus | |
| Component | A | B |
| Right ascension | 23h 18m | 23h 18m |
| 37.493s | 37.115s | |
| Declination | +68° 06′[1] | +68° 06′[2] |
| 41.20″ | 38.65″ | |
| Apparent magnitude (V) | 4.86[3] | 7.13[3] |
| Characteristics | ||
| Spectral type | G8III[4] | F6V[3] |
| U-B color index | +0.49[3] | |
| B-V color index | +0.84[3] | |
| R-I color index | +0.45[3] | |
| Astrometry | ||
| Proper motion: | ||
| RA (μα cos δ) | 54.88[1] mas/yr | 45.70[2] mas/yr |
| Dec. (μδ) | 10.91[1] mas/yr | 13.19[2] mas/yr |
| Parallax (π) | 15.48 ± 0.55[5] mas | |
| Distance | 211 ± 7 ly (65 ± 2 pc) | |
| Absolute magnitude (MV) | 0.8[note 1] | 3.1[note 1] |
| Details | ||
| Mass | 2.35 ± 0.15[4] M☉ | 1.29[4] M☉ |
| Orbit[4] | ||
| Period (P) | 1505 ± 40 y | |
| Semimajor axis (a) | 3.13 ± 0.12″ | |
| Eccentricity (e) | 0.439 ± 0.020 | |
| Inclination (i) | 16.0 ± 4.0° | |
| Longitude of node (Ω) | 4.5 ± 4.5° | |
| Periastron epoch (T) | B1692 ± 20 | |
| Argument of periastron (ω) (secondary) | 93.0 ± 20.0° | |
| Database references | ||
| SIMBAD | data | |
| Other designations | ||
Omicron Cephei (Omicron Cep, ο Cephei, ο Cep) is a binary star in the constellation of Cepheus.[5] It consists of a less massive K-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.[3]
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 Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Cepheus |
| Right ascension | 23h 18m 37.5s[7] |
| Declination | +68° 07′ 26″[7] |
| Apparent magnitude (V) | 12.8[7] |
| Position (relative to A) | |
| Epoch of observation | 1912 |
| Angular distance | 45.6″ [6] |
| Position angle | 4° [6] |
| 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.[6][7]
Notes
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 Component 2, HIP 115088, database entry, The Hipparcos and Tycho Catalogues, 1997, CDS ID I/239.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 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.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Orbit and System Mass for the Visual Binary WDS 23186+6807AB, José A. Docobo, Vakhtang S. Tamazian, Manuel Andrade, and Norik D. Melikian, Astronomical Journal 126, #3 (September 2003), pp. 1522–1525, Bibcode: 2003AJ....126.1522D, doi:10.1086/377319.
- ↑ 5.0 5.1 5.2 CCDM J23186+6807AB -- Double or multiple star, database entry, SIMBAD. Accessed on line November 24, 2008.
- ↑ 6.0 6.1 6.2 6.3 6.4 Entry 23186+6807, The Washington Double Star Catalog, United States Naval Observatory. Accessed on line November 24, 2008.
- ↑ 7.0 7.1 7.2 7.3 7.4 CCDM J23186+6807C -- Star in double system, database entry, SIMBAD. Accessed on line November 24, 2008.
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