Zeta Gruis, Latinised from ζ Gruis, is a solitary[7] star in the southern constellation of Grus. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 4.12.[2] Based upon an annual parallax shift of 24.5 mas as seen from the Earth,[1] the system is located about 133 light-years from the Sun.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Grus |
| Right ascension | 23h 00m 52.79777s[1] |
| Declination | −52° 45′ 14.8705″[1] |
| Apparent magnitude (V) | 4.12[2] |
| Characteristics | |
| Spectral type | K1 III Fe−1.2 CN−0.5[3] |
| U−B color index | +0.722[2] |
| B−V color index | +0.967[2] |
| Astrometry | |
| Radial velocity (Rv) | −1.1±2.7[4] km/s |
| Proper motion (μ) | RA: −57.911[1] mas/yr Dec.: −13.371[1] mas/yr |
| Parallax (π) | 24.5452 ± 0.5124 mas[1] |
| Distance | 133 ± 3 ly (40.7 ± 0.9 pc) |
| Absolute magnitude (MV) | +1.49[5] |
| Details | |
| Radius | 9.86+0.32 −0.65[1] R☉ |
| Luminosity | 45.6±1.1[1] L☉ |
| Temperature | 4,778+166 −75[1] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
This is an evolved K-type giant star with a stellar classification of K1 III Fe−1.2 CN−0.5,[3] where the suffix notation indicates underabundances of iron and cyanogen in the spectrum. Having exhausted the supply of hydrogen at its core, the star has expanded and cooled; at present it has 10[1] times the girth of the Sun. The star is radiating 46[1] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,778 K.[1]