Omicron Gruis
Variable star in the constellation Grus From Wikipedia, the free encyclopedia
Variable star in the constellation Grus From Wikipedia, the free encyclopedia
ο Gruis, Latinised as Omicron Gruis, is a binary or triple star[4] system in the southern constellation of Grus. It is faintly visible to the naked eye with an apparent visual magnitude of 5.52.[2] Based upon an annual parallax shift of 32.50 mas as seen from the Earth,[1] the system is located 100 light years from the Sun.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Grus |
| Right ascension | 23h 26m 36.57748s[1] |
| Declination | −52° 43′ 17.7656″[1] |
| Apparent magnitude (V) | 5.52[2] |
| Characteristics | |
| Spectral type | F4 V[3] + M3/M4[4] |
| B−V color index | +0.40[2] |
| Variable type | δ Sct[5] |
| Astrometry | |
| Proper motion (μ) | RA: +34.52[1] mas/yr Dec.: +130.66[1] mas/yr |
| Parallax (π) | 32.50 ± 0.37 mas[1] |
| Distance | 100 ± 1 ly (30.8 ± 0.4 pc) |
| Absolute magnitude (MV) | 3.01[6] |
| Details | |
| ο Gru A | |
| Mass | 1.31[7] M☉ |
| Surface gravity (log g) | 4.19[7] cgs |
| Temperature | 6,763±230[7] K |
| Metallicity [Fe/H] | –0.10[3] dex |
| Rotational velocity (v sin i) | 20.4±0.3[6] km/s |
| Age | 1.026[7] Gyr |
| ο Gru B | |
| Mass | 0.3[4] M☉ |
| Age | 1.1[4] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
The pair form a close spectroscopic binary system with a physical separation of about 14.9 astronomical units.[4] The primary component is an F-type main sequence star with a stellar classification of F4 V,[3] a star that is currently fusing its core hydrogen. It is a probable delta scuti variable showing periodicities of 4.7 and 5.5 cycles per day with amplitudes of 0.014 and 0.011 magnitudes, respectively.[5] The secondary companion is a red dwarf with a mass of about 0.3 solar, suggesting a class of M3/M4.[4] Ehrenreich et al. (2010) noted the detection of a tertiary companion that is not causing the detected radial velocity shifts which would make this a triple star system.[4]
