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]
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]
|