Zeta Hydrae
Zeta Hydrae (ζ Hya, ζ Hydrae) is a solitary star in the equatorial constellation of Hydra. This is a generally faint constellation, so, at an apparent visual magnitude of +3.10, this is the third-brightest member after Alphard and Gamma Hydrae.
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Hydra |
| Right ascension | 08h 55m 23.62614s |
| Declination | +05° 56′ 44.0354″ |
| Apparent magnitude (V) | 3.10 |
| Characteristics | |
| Spectral type | G9 II-III |
| U−B color index | +0.82 |
| B−V color index | +1.00 |
| Astrometry | |
| Radial velocity (Rv) | +22.8 km/s |
| Proper motion (μ) | RA: –100.06 mas/yr Dec.: +15.46 mas/yr |
| Parallax (π) | 19.51 ± 0.18 mas |
| Distance | 167 ± 2 ly (51.3 ± 0.5 pc) |
| Absolute magnitude (MV) | –0.24 |
| Details | |
| Mass | 4.2 M☉ |
| Radius | 17.9 R☉ |
| Luminosity | 132 L☉ |
| Surface gravity (log g) | 2.48 cgs |
| Temperature | 4,925 K |
| Metallicity [Fe/H] | –0.21 dex |
| Rotational velocity (v sin i) | 2.5 km/s |
| Age | 400 Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
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