Mimosa (star)
Mimosa is the second-brightest object in the southern constellation of Crux (after Acrux), and the 20th-brightest star in the night sky. It has the Bayer designation β Crucis, which is Latinised to Beta Crucis and abbreviated Beta Cru or β Cru. Mimosa forms part of the prominent asterism called the Southern Cross. It is a binary star or a possible triple star system.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Crux |
| Pronunciation | /mɪˈmoʊsə/ |
| Right ascension | 12h 47m 43.26877s |
| Declination | −59° 41′ 19.5792″ |
| Apparent magnitude (V) | 1.25 (1.23 - 1.31) |
| Characteristics | |
| Spectral type | B0.5 III / B2V |
| U−B color index | −0.98 |
| B−V color index | −0.23 |
| Variable type | β Cep |
| Astrometry | |
| Radial velocity (Rv) | +15.6 km/s |
| Proper motion (μ) | RA: −42.97 mas/yr Dec.: −16.18 mas/yr |
| Parallax (π) | 11.71 ± 0.98 mas |
| Distance | 280 ± 20 ly (85 ± 7 pc) |
| Absolute magnitude (MV) | −3.92 |
| Orbit | |
| Primary | β Crucis A |
| Companion | β Crucis B |
| Period (P) | 1828.0±2.5 days |
| Semi-major axis (a) | 8.7 AU |
| Eccentricity (e) | 0.38±0.09 |
| Periastron epoch (T) | 2,449,879±38 HJD |
| Argument of periastron (ω) (secondary) | 293±9° |
| Details | |
| A | |
| Mass | 16 M☉ |
| Radius | 8.4±0.6 R☉ |
| Luminosity | 34,000 L☉ |
| Surface gravity (log g) | 3.6±0.1 cgs |
| Temperature | 27,000±1,000 K |
| Metallicity [Fe/H] | −0.08 dex |
| Rotation | 3.6 days |
| Rotational velocity (v sin i) | 35 km/s |
| Age | 8 to 11 Myr |
| B | |
| Mass | 10 M☉ |
| Other designations | |
| Database references | |
| SIMBAD | data |
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