Omicron Cephei (Omicron Cep, ο Cephei, ο Cep) is a binary star in the constellation of Cepheus. It consists of a less massive K-type main sequence star in orbit with a more massive G-type giant star. The overall apparent visual magnitude of the system is 4.75.
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.
Epoch J2000.0 Equinox J2000.0 (ICRS)
|Right ascension||23h 18m 37.5s|
|Declination||+68° 07′ 26″|
|Apparent magnitude (V)||12.8|
|Position (relative to A)|
|Epoch of observation||1912|
|Angular distance||45.6″ |
|Position angle||4° |
- From apparent magnitude and parallax.
- Component 1, HIP 115088, database entry, The Hipparcos and Tycho Catalogues, 1997, CDS ID I/239.
- 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.
- Component 2, HIP 115088, database entry, The Hipparcos and Tycho Catalogues, 1997, CDS ID I/239.
- 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.
- CCDM J23186+6807AB -- Double or multiple star, database entry, SIMBAD. Accessed on line November 24, 2008.
- Entry 23186+6807, The Washington Double Star Catalog, United States Naval Observatory. Accessed on line November 24, 2008.
- CCDM J23186+6807C -- Star in double system, database entry, SIMBAD. Accessed on line November 24, 2008.