Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Hydra |
Right ascension | 10h 26m 05.42630s[1] |
Declination | −14° 19′ 56.2675″[1] |
Apparent magnitude (V) | 3.83[2] |
Characteristics | |
Spectral type | K4 III[3] |
U−B color index | +1.83[2] |
B−V color index | +1.47[2] |
Variable type | Suspected[4] |
Astrometry | |
Radial velocity (Rv) | +40.81±0.36[5] km/s |
Proper motion (μ) | RA: −129.17[1] mas/yr Dec.: −79.76[1] mas/yr |
Parallax (π) | 13.93 ± 0.18 mas[1] |
Distance | 234 ± 3 ly (71.8 ± 0.9 pc) |
Absolute magnitude (MV) | −0.45[6] |
Details[5] | |
Radius | 45 R☉ |
Luminosity | 332[6] L☉ |
Surface gravity (log g) | 1.5 cgs |
Temperature | 3,999±8 K |
Metallicity [Fe/H] | −0.12 dex |
Rotational velocity (v sin i) | 6.0 km/s |
Other designations | |
Database references | |
SIMBAD | data |
μ Hydrae, Latinised as Mu Hydrae, is a solitary,[8] orange-hued star in the equatorial constellation of Hydra. It is visible to the naked eye with an apparent visual magnitude of 3.83.[2] Positioned just 1.8° to the south-southwest is the planetary nebula NGC 3242.[9] Mu Hydrae has an annual parallax shift of 13.93 mas,[1] which yields a distance estimate of 234 light years.
This is an evolved K-type giant star with a stellar classification of K4 III,[3] having used up its core hydrogen and has expanded to around 45 times the radius of the Sun.[5] It is a suspected variable star, with a brightness that varies about 0.03 in magnitude.[4] The relatively cool outer atmosphere has an effective temperature of 3999 K.[5]