Sigma2 Tauri
Star in the constellation Taurus
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Sigma2 Tauri (σ2 Tauri) is the Bayer designation for a white-hued star in the zodiac constellation of Taurus. It has an apparent visual magnitude of +4.70,[3] which indicates it is visible to the naked eye. Based upon parallax measurements, σ2 Tauri is about 156 light-years distant.
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Taurus[1] |
| Right ascension | 04h 39m 16.50230s[2] |
| Declination | +15° 55′ 04.7029″[2] |
| Apparent magnitude (V) | 4.70[3] |
| Characteristics | |
| Evolutionary stage | main sequence[4] |
| Spectral type | A5 Vn[5] |
| U−B color index | +0.13[3] |
| B−V color index | +0.14[3] |
| Astrometry | |
| Radial velocity (Rv) | +40.8±1.2[6] km/s |
| Proper motion (μ) | RA: +83.17[2] mas/yr Dec.: −20.97[2] mas/yr |
| Parallax (π) | 20.97±0.27 mas[2] |
| Distance | 156 ± 2 ly (47.7 ± 0.6 pc) |
| Absolute magnitude (MV) | +1.28[1] |
| Details | |
| Mass | 1.71[7] M☉ |
| Radius | 1.9[8] R☉ |
| Luminosity | 22.5[9] L☉ |
| Surface gravity (log g) | 3.96[7] cgs |
| Temperature | 8,165±278[7] K |
| Metallicity [Fe/H] | 0.10±0.11[10] dex |
| Rotational velocity (v sin i) | 128[5] km/s |
| Age | 258[7] Myr |
| Other designations | |
| 92 Tauri, BD+15°666, FK5 2345, HD 29488, HIP 21683, HR 1479, SAO 94054, WDS J04393+1555A[11] | |
| Database references | |
| SIMBAD | data |
σ2 Tauri is a solitary[12] A-type main sequence star with a stellar classification of A5 Vn.[5] The 'n' suffix indicates the lines are "nebulous" due to rapid rotation, and indeed it is spinning with a projected rotational velocity of 128 km/s.[5] The star is an estimated 258[7] million years old, with 1.7[7] times the mass of the Sun. It is radiating 22.5[9] times the Sun's luminosity from its photosphere at an effective temperature of around 8,165 K.[7] The star is considered a member of the Hyades cluster.[8]
In Chinese astronomy, σ2 Tauri is called 附耳, Pinyin: Fùěr, meaning Whisper, because this star is marking itself and stands alone in the Whisper asterism of the Net mansion (see: Chinese constellation).[13]