Mira
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.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cetus |
| Right ascension | 02h 19m 20.79210s |
| Declination | −02° 58′ 39.4956″ |
| Apparent magnitude (V) | 2.0 to 10.1 |
| Characteristics | |
| Spectral type | M7 IIIe (M5e-M9e) |
| U−B color index | +0.08 |
| B−V color index | +1.53 |
| Variable type | Mira |
| Astrometry | |
| Radial velocity (Rv) | +63.8 km/s |
| Proper motion (μ) | RA: +9.33 mas/yr Dec.: −237.36 mas/yr |
| Parallax (π) | 10.91 ± 1.22 mas |
| Distance | approx. 300 ly (approx. 90 pc) |
| Absolute magnitude (MV) | +0.99 (variable) |
| Orbit | |
| 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 M☉ |
| Radius | 332–402 (-541) R☉ |
| Luminosity (bolometric) | 8,400–9,360 L☉ |
| Temperature | 2,918–3,192 K |
| Age | 6 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
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.
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