Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Hydrus |
Right ascension | 02h 21m 44.94286s[1] |
Declination | −68° 39′ 33.9038″[1] |
Apparent magnitude (V) | 4.09[2] |
Characteristics | |
Spectral type | A2 V[3] |
U−B color index | +0.05[2] |
B−V color index | +0.03[2] |
Astrometry | |
Radial velocity (Rv) | +6.00[4] km/s |
Proper motion (μ) | RA: -49.95[1] mas/yr Dec.: +2.48[1] mas/yr |
Parallax (π) | 23.35 ± 0.34 mas[1] |
Distance | 140 ± 2 ly (42.8 ± 0.6 pc) |
Absolute magnitude (MV) | 0.92[3] |
Details | |
Mass | 2.25[5] M☉ |
Radius | 2.3[5] R☉ |
Luminosity | 39.52[3] L☉ |
Surface gravity (log g) | 3.98[6] cgs |
Temperature | 9,880±336[6] K |
Metallicity [Fe/H] | +0.12[3] dex |
Rotational velocity (v sin i) | 162[6] km/s |
Age | 209[6] Myr |
Other designations | |
Database references | |
SIMBAD | data |
Delta Hydri, Latinized from δ Hydri, is a single,[7] white-hued star in the southern constellation of Hydrus. It is bright enough to be faintly visible to the naked eye with an apparent visual magnitude of 4.09.[2] The distance to this star, based upon an annual parallax shift of 23.35 mas,[1] is about 140 light years. It is moving away from the Sun with a radial velocity of +6 km/s.[4]
This is an ordinary A-type main-sequence star with a stellar classification of A2 V[3] It is about 209 million years old and has a high rate of spin, showing a projected rotational velocity of 162 km/s.[6] This is giving the star an oblate shape with an equatorial bulge that is 7% larger than the polar radius.[8] The star has 2.25 times the mass of the Sun and 2.3 times the Sun's radius.[5] It is radiating 39.5[3] times the Sun's luminosity from its photosphere at an effective temperature of around 9.880.[6] Delta Hydri has been checked for an infrared excess, but none was found.[7]