| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Hydra |
| Right ascension | 09h 39m 51.36145s[1] |
| Declination | −01° 08′ 34.1135″[1] |
| Apparent magnitude (V) | 3.91[2] |
| Characteristics | |
| Spectral type | K2.5 III[2] |
| B−V color index | 1.32 |
| Variable type | Suspected[3] |
| Astrometry | |
| Radial velocity (Rv) | +24.19±0.36[4] km/s |
| Proper motion (μ) | RA: +46.96[1] mas/yr Dec.: −62.39[1] mas/yr |
| Parallax (π) | 12.39 ± 0.14 mas[1] |
| Distance | 263 ± 3 ly (80.7 ± 0.9 pc) |
| Absolute magnitude (MV) | −0.63[5] |
| Details | |
| Mass | 1.92[2] M☉ |
| Radius | 30±0.04[6] R☉ |
| Luminosity | 83[2] L☉ |
| Surface gravity (log g) | 2.2[4] cgs |
| Temperature | 4,244±32[2] K |
| Metallicity [Fe/H] | −0.05[2] dex |
| Rotational velocity (v sin i) | 4.5[4] km/s |
| Age | 2.47[2] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Iota Hydrae (ι Hydrae, abbreviated Iota Hya, ι Hya), formally named Ukdah /ˈʌkdə/,[8] is a star in the constellation of Hydra, about 8° to the north-northwest of Alphard (Alpha Hydrae)[9] and just to the south of the celestial equator.[10] Visible to the naked eye, it is a suspected variable star with an apparent visual magnitude that ranges between 3.87 and 3.91.[3] Based upon an annual parallax shift of 12.39 mas measured during the Hipparcos mission,[1] it is located around 263 light-years from the Sun.
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