Nu Hydri
Star in the constellation Hydrus
From Wikipedia, the free encyclopedia
ν Hydri, Latinized as Nu Hydri, is a single[10] star in the southern circumpolar constellation of Hydrus. It is orange-hued and faintly visible to the naked eye with an apparent visual magnitude of 4.76.[2] This object is located approximately 331 light years from the Sun based on parallax, and is drifting further away with a radial velocity of +3 km/s.[1] It is a member of the Ursa Major Moving Group of stars that share a common motion through space.[11]
 | |
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Hydrus |
| Right ascension | 02h 50m 28.45915s[1] |
| Declination | −75° 04′ 00.9969″[1] |
| Apparent magnitude (V) | 4.76[2] |
| Characteristics | |
| Spectral type | K3III[3] |
| U−B color index | +1.56[4] |
| B−V color index | +1.33[4] |
| Astrometry | |
| Radial velocity (Rv) | +3.09±0.16[1] km/s |
| Proper motion (μ) | RA: −33.392[1] mas/yr Dec.: −27.286[1] mas/yr |
| Parallax (π) | 9.8538±0.1433 mas[1] |
| Distance | 331 ± 5 ly (101 ± 1 pc) |
| Absolute magnitude (MV) | −0.33[2] |
| Details | |
| Mass | 3.5[5] or 1.79[6] M☉ |
| Radius | 21.23+3.23 −4.50[1] R☉ |
| Luminosity | 183.8±3.2[1] L☉ |
| Surface gravity (log g) | 3.30[7] cgs |
| Temperature | 4,612+584 −315[1] K |
| Metallicity [Fe/H] | −1.52[7] dex |
| Rotation | 50 d[5] |
| Rotational velocity (v sin i) | 1.3[8] km/s |
| Age | 2.38[6] Gyr |
| Other designations | |
| ν Hyi, CPD−75°204, FK5 2199, GC 3463, HD 18293, HIP 13244, HR 872, SAO 255929[9] | |
| Database references | |
| SIMBAD | data |
This is an aging giant star with a stellar classification of K3III.[3] With the supply of hydrogen at its core exhausted, the star has expanded and cooled. At present it has 21[1] times the girth of the Sun. It is 2.4[6] billion years old with estimates of its mass ranging from 1.8[6] to 3.5[5] times the mass of the Sun. The star is radiating 184[1] times the Sun's luminosity from its swollen photosphere at an effective temperature of 4,612 K.[1]