Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Tucana |
Right ascension | 22h 33m 00.06240s[2] |
Declination | −61° 58′ 55.6390″[2] |
Apparent magnitude (V) | 4.75 - 4.93[3] |
Characteristics | |
Spectral type | M4 III[4] |
U−B color index | +1.73[5] |
B−V color index | +1.61[5] |
Variable type | Lb:[6] |
Astrometry | |
Radial velocity (Rv) | −3.4±0.8[7] km/s |
Proper motion (μ) | RA: −3.40[2] mas/yr Dec.: −0.8[2] mas/yr |
Parallax (π) | 11.24 ± 0.23 mas[2] |
Distance | 290 ± 6 ly (89 ± 2 pc) |
Absolute magnitude (MV) | +0.16[8] |
Details | |
Radius | 49.39+5.65 −7.73[9] R☉ |
Luminosity | 400±11[9] L☉ |
Temperature | 3,674+326 −194[9] K |
Other designations | |
Database references | |
SIMBAD | data |
ν Tucanae, Latinized as Nu Tucanae, is a solitary,[11] variable star in the southern constellation of Tucana. This red-hued object is visible to the naked eye as a faint star with an apparent visual magnitude that fluctuates around +4.80.[5] It is located approximately 290 light years from the Sun based on parallax,[2] but is drifting closer with a radial velocity of −3 km/s.[7]
This object is an aging red giant with a stellar classification of M4 III,[4] currently on the asymptotic giant branch.[6] With the supply of hydrogen exhausted at its core, the star has cooled and expanded off the main sequence; at present it has 49 times the Sun's radius.[9] It is classified as a slow irregular variable and its brightness varies from magnitude +4.75 to +4.93.[3] Cyclical periods of 22.3, 24.4, 24.8, 25.1, 25.5, 33.8, 50.6, 80.1, 123.2, and 261.8 days have been reported for its variations.[12] On average, the star is radiating around 400[9] times the luminosity of the Sun from its photosphere at an effective temperature of 3,674 K.[9]