Delta Hydrae
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Hydra |
| Right ascension | 08h 37m 39.36627s |
| Declination | +05° 42′ 13.6057″ |
| Apparent magnitude (V) | 4.146 |
| Characteristics | |
| δ Hydrae Aa | |
| Spectral type | A1 Vnn |
| U−B color index | +0.003 |
| B−V color index | +0.008 |
| Astrometry | |
| Radial velocity (Rv) | 4.10 km/s |
| Proper motion (μ) | RA: −70.19 mas/yr Dec.: −7.90 mas/yr |
| Parallax (π) | 20.34±0.63 mas |
| Distance | 160 ± 5 ly (49 ± 2 pc) |
| Absolute magnitude (MV) | +0.68 |
| Position (relative to δ Hydrae A) | |
| Component | δ Hydrae B |
| Angular distance | 2.6±0.1″ |
| Position angle | 265.1±1.0° |
| Projected separation | 147 AU |
| Orbit | |
| Primary | Aa |
| Companion | Ab |
| Period (P) | ~200 days |
| Semi-major axis (a) | 0.9 AU |
| Details | |
| δ Hydrae Aa | |
| Mass | 2.43 M☉ |
| Radius | 3.1 R☉ |
| Luminosity | 42.7 L☉ |
| Temperature | 8,995 K |
| Rotational velocity (v sin i) | 285 km/s |
| Age | 500 Myr |
| δ Hydrae Ab | |
| Mass | 0.58 M☉ |
| Radius | 0.54 R☉ |
| Temperature | 3,973 K |
| Age | 500 Myr |
| δ Hydrae B | |
| Mass | 0.44 M☉ |
| Other designations | |
| δ Hya, 4 Hydrae, BD+06°2001, FK5 1223, HD 73262, HIP 42313, HR 3410, SAO 116965 | |
| Database references | |
| SIMBAD | data |
Delta Hydrae, Latinized from δ Hydrae, is a triple star in the equatorial constellation of Hydra. It is visible to the naked eye with an apparent visual magnitude of 4.146. Based upon an annual parallax shift of 20.34 mas, it is located about 160 light years distant.