  | |
| Observation data EpochJ2000.0 EquinoxJ2000.0 (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−Bcolor index | +1.83[2] |
| B−Vcolor 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 | |
| μ Hya, 42 Hydrae,BD−16°3052,FK5 389,HD 90432,HIP 51069,HR 4094,SAO 155980.[7] | |
| Database references | |
| SIMBAD | data |
μ Hydrae, Latinised asMu Hydrae, is a solitary,[8] orange-huedstar in the equatorialconstellation ofHydra. It is visible to the naked eye with anapparent visual magnitude of 3.83.[2] Positioned just 1.8° to the south-southwest is theplanetary nebulaNGC 3242.[9] Mu Hydrae has an annualparallax shift of 13.93 mas,[1] which yields a distance estimate of 234 light years.
This is anevolvedK-typegiant star with astellar classification of K4 III,[3] having used up its corehydrogen and has expanded to around 45 times theradius of the Sun.[5] It is a suspectedvariable star, with a brightness that varies about 0.03 in magnitude.[4] The relatively coolouter atmosphere has aneffective temperature of 3999 K.[5]
