Mira
Binary star in Cetus / From Wikipedia, the free encyclopedia
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For other uses, see Mira (disambiguation).
Mira (/ˈmaɪrə/), designation Omicron Ceti (ο Ceti, abbreviated Omicron Cet, ο Cet), is a red-giant star estimated to be 200–300 light-years from the Sun in the constellation Cetus.
Quick Facts Constellation, Right ascension ...
Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Cetus |
Right ascension | 02h 19m 20.79210s[2] |
Declination | −02° 58′ 39.4956″[2] |
Apparent magnitude (V) | 2.0 to 10.1[3] |
Characteristics | |
Spectral type | M7 IIIe[4] (M5e-M9e[3]) |
U−B color index | +0.08[5] |
B−V color index | +1.53[5] |
Variable type | Mira[3] |
Astrometry | |
Radial velocity (Rv) | +63.8[6] km/s |
Proper motion (μ) | RA: +9.33[2] mas/yr Dec.: −237.36[2] mas/yr |
Parallax (π) | 10.91 ± 1.22 mas[2] |
Distance | approx. 300 ly (approx. 90 pc) |
Absolute magnitude (MV) | +0.99[7] (variable) |
Orbit[8] | |
Period (P) | 497.88 yr |
Semi-major axis (a) | 0.8″ |
Eccentricity (e) | 0.16 |
Inclination (i) | 112° |
Longitude of the node (Ω) | 138.8° |
Periastron epoch (T) | 2285.75 |
Argument of periastron (ω) (secondary) | 258.3° |
Details | |
Mass | 1.18[9] M☉ |
Radius | 332–402[10] (-541[11]) R☉ |
Luminosity (bolometric) | 8,400–9,360[10] L☉ |
Temperature | 2,918–3,192[10] K |
Age | 6[9] Gyr |
Other designations | |
Database references | |
SIMBAD | data |
Close
ο Ceti is a binary stellar system, consisting of a variable red giant (Mira A) along with a white dwarf companion (Mira B). Mira A is a pulsating variable star and was the first non-supernova variable star discovered, with the possible exception of Algol. It is the prototype of the Mira variables.