Iota Hydrae
Iota Hydrae (ι Hydrae, abbreviated Iota Hya, ι Hya), formally named Ukdah /ˈʌkdə/, is a star in the constellation of Hydra, about 8° to the north-northwest of Alphard (Alpha Hydrae) and just to the south of the celestial equator. Visible to the naked eye, it is a suspected variable star with an apparent visual magnitude that ranges between 3.87 and 3.91. Based upon an annual parallax shift of 12.39 mas measured during the Hipparcos mission, it is located around 263 light-years from the Sun.
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Hydra |
| Right ascension | 09h 39m 51.36145s |
| Declination | −01° 08′ 34.1135″ |
| Apparent magnitude (V) | 3.91 |
| Characteristics | |
| Spectral type | K2.5 III |
| B−V color index | 1.32 |
| Variable type | Suspected |
| Astrometry | |
| Radial velocity (Rv) | +24.19±0.36 km/s |
| Proper motion (μ) | RA: +46.96 mas/yr Dec.: −62.39 mas/yr |
| Parallax (π) | 12.39 ± 0.14 mas |
| Distance | 263 ± 3 ly (80.7 ± 0.9 pc) |
| Absolute magnitude (MV) | −0.63 |
| Details | |
| Mass | 1.92 M☉ |
| Radius | 33 R☉ |
| Luminosity | 83 L☉ |
| Surface gravity (log g) | 2.2 cgs |
| Temperature | 4,244±32 K |
| Metallicity [Fe/H] | −0.05 dex |
| Rotational velocity (v sin i) | 4.5 km/s |
| Age | 2.47 Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
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