Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS) | |
---|---|
Constellation | Grus |
Right ascension | 22h 48m 33.29833s [1] |
Declination | −51° 19′ 00.7001″ [1] |
Apparent magnitude (V) | 3.466 [2] |
Characteristics | |
Spectral type | A2 IVn [3] |
B−V color index | 0.09 [2] |
Astrometry | |
Radial velocity (Rv) | −0.4±2.1 [4] km/s |
Proper motion (μ) |
RA: +108.43
[1]
mas/
yr Dec.: −64.83 [1] mas/ yr |
Parallax (π) | 25.30 ± 0.48 mas [1] |
Distance | 129 ± 2
ly (39.5 ± 0.7 pc) |
Absolute magnitude (MV) | +0.52 [5] |
Details | |
Mass | 1.85 [6] M☉ |
Surface gravity (log g) | 3.47±0.14 [6] cgs |
Temperature | 8,685±295 [6] K |
Metallicity [Fe/H] | −0.16 [3] dex |
Rotational velocity (v sin i) | 235.1±11.8 [5] km/s |
Age | 249 [6] Myr |
Other designations | |
Database references | |
SIMBAD | data |
ε Gruis, Latinised as Epsilon Gruis, is a blue-white hued star in the southern constellation of Grus. It is visible to the naked eye, having an apparent visual magnitude of 3.5. [2] Based upon an annual parallax shift of 25.30 mas as measured from Earth, [1] it is located around 129 light years from the Sun. The system may be moving closer to the Sun with a radial velocity of about −0.4 km/s. [4]
This is an A-type subgiant of spectral type A2IVn, [3] a star that has used up its core hydrogen and has begun to expand off the main sequence. At the estimated age of 249 million years, [6] it is spinning rapidly with a projected rotational velocity of 235 km/s. [5] This is giving the star an oblate shape with an equatorial bulge that is an estimated 18% larger than the polar radius. [8] The star displays an infrared excess, suggesting the presence of a circumstellar disk of orbiting dust. [9]
Epsilon Gruis is suspected of having a moderately active [10] close companion, [11] which is most likely the source of the weak X-ray emission from these coordinates with a luminosity of 1.3×1028 erg s−1. [10]
Observation data Epoch J2000.0 Equinox J2000.0 ( ICRS) | |
---|---|
Constellation | Grus |
Right ascension | 22h 48m 33.29833s [1] |
Declination | −51° 19′ 00.7001″ [1] |
Apparent magnitude (V) | 3.466 [2] |
Characteristics | |
Spectral type | A2 IVn [3] |
B−V color index | 0.09 [2] |
Astrometry | |
Radial velocity (Rv) | −0.4±2.1 [4] km/s |
Proper motion (μ) |
RA: +108.43
[1]
mas/
yr Dec.: −64.83 [1] mas/ yr |
Parallax (π) | 25.30 ± 0.48 mas [1] |
Distance | 129 ± 2
ly (39.5 ± 0.7 pc) |
Absolute magnitude (MV) | +0.52 [5] |
Details | |
Mass | 1.85 [6] M☉ |
Surface gravity (log g) | 3.47±0.14 [6] cgs |
Temperature | 8,685±295 [6] K |
Metallicity [Fe/H] | −0.16 [3] dex |
Rotational velocity (v sin i) | 235.1±11.8 [5] km/s |
Age | 249 [6] Myr |
Other designations | |
Database references | |
SIMBAD | data |
ε Gruis, Latinised as Epsilon Gruis, is a blue-white hued star in the southern constellation of Grus. It is visible to the naked eye, having an apparent visual magnitude of 3.5. [2] Based upon an annual parallax shift of 25.30 mas as measured from Earth, [1] it is located around 129 light years from the Sun. The system may be moving closer to the Sun with a radial velocity of about −0.4 km/s. [4]
This is an A-type subgiant of spectral type A2IVn, [3] a star that has used up its core hydrogen and has begun to expand off the main sequence. At the estimated age of 249 million years, [6] it is spinning rapidly with a projected rotational velocity of 235 km/s. [5] This is giving the star an oblate shape with an equatorial bulge that is an estimated 18% larger than the polar radius. [8] The star displays an infrared excess, suggesting the presence of a circumstellar disk of orbiting dust. [9]
Epsilon Gruis is suspected of having a moderately active [10] close companion, [11] which is most likely the source of the weak X-ray emission from these coordinates with a luminosity of 1.3×1028 erg s−1. [10]