Gamma Arae
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ara |
| Right ascension | 17h 25m 23.65931s |
| Declination | −56° 22′ 39.8148″ |
| Apparent magnitude (V) | 3.34 |
| Characteristics | |
| Spectral type | B1 Ib |
| U−B color index | −0.96 |
| B−V color index | −0.13 |
| Astrometry | |
| Radial velocity (Rv) | −3±2.9 km/s |
| Proper motion (μ) | RA: −0.44 mas/yr Dec.: −15.77 mas/yr |
| Parallax (π) | 2.93±0.16 mas |
| Distance | 1,110 ± 60 ly (340 ± 20 pc) |
| Absolute magnitude (MV) | −5.8 |
| Details | |
| Mass | 12.5 M☉ 19 M☉ |
| Radius | 14.20±0.28 R☉ |
| Luminosity | 120,000 L☉ |
| Surface gravity (log g) | 3.50±0.04 cgs |
| Temperature | 21,240±212 K |
| Rotation | 4.8 days |
| Rotational velocity (v sin i) | 269±11 km/s |
| Age | 15.7±0.1 Myr |
| Other designations | |
| γ Ara, CPD−56°8225, GC 23517, HD 157246, HIP 85267, HR 6462, SAO 244726, PPM 345992, WDS J17254-5623A | |
| Database references | |
| SIMBAD | data |
Gamma Arae is a massive star in the southern constellation of Ara. Its name is a Bayer designation that is Latinized from γ Arae, and abbreviated Gamma Ara or γ Ara. With an apparent visual magnitude of 3.3, it is the fourth-brightest star in the constellation and is readily visible to the naked eye. From parallax measurements made during the Hipparcos mission, the distance to this star can be estimated as 1,110 light-years (340 parsecs) from Earth.
The proper motion of this star traces back to the Scorpius region of the Galactic Plane, about 20–25° away. Gamma Arae has an optical companion located at an angular separation of 17.9 arcseconds, which is an A-type main sequence star with an apparent magnitude of 10.5.