Gacrux
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Crux |
| Right ascension | 12h 31m 09.960s |
| Declination | −57° 06′ 47.57″ |
| Apparent magnitude (V) | +1.64 |
| Characteristics | |
| Evolutionary stage | Red giant branch |
| Spectral type | M3.5 III |
| Apparent magnitude (J) | −1.99 |
| U−B color index | +1.78 |
| B−V color index | +1.59 |
| Variable type | SRV |
| Astrometry | |
| Radial velocity (Rv) | +20.6 km/s |
| Proper motion (μ) | RA: +28.23 mas/yr Dec.: −265.08 mas/yr |
| Parallax (π) | 36.83±0.18 mas |
| Distance | 88.6 ± 0.4 ly (27.2 ± 0.1 pc) |
| Absolute magnitude (MV) | −0.68±0.01 |
| Details | |
| Mass | 1.5±0.2 M☉ |
| Radius | 73 R☉ |
| Luminosity | 830 L☉ |
| Surface gravity (log g) | 0.75±0.02 cgs |
| Temperature | 3689±125 K |
| Other designations | |
| Gacrux, γ Crucis, CD−56 4504, HD 108903, HIP 61084, HR 4763, SAO 240019, LTT 4752 | |
| Database references | |
| SIMBAD | data |
Gacrux is the third-brightest star in the southern constellation of Crux, the Southern Cross. It has the Bayer designation Gamma Crucis, which is Latinised from γ Crucis and abbreviated Gamma Cru or γ Cru. With an apparent visual magnitude of +1.63, it is the 26th brightest star in the night sky. A line from the two "Pointers", Alpha Centauri through Beta Centauri, leads to within 1° north of this star. Using parallax measurements made during the Hipparcos mission, it is 88.6 light-years (27.2 parsecs) distant. It is the nearest M-type red giant star.