Sigma1 Tauri
Star in the constellation Taurus
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Sigma1 Tauri (σ1 Tauri) is the Bayer designation for a white-hued star in the zodiac constellation of Taurus. It has an apparent visual magnitude of +5.07,[2] which indicates it is visible to the naked eye. Based upon parallax measurements, σ1 Tauri is about 147 light-years from the Sun.
 | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Taurus |
| Right ascension | 04h 39m 09.22247s[1] |
| Declination | +15° 47′ 59.5345″[1] |
| Apparent magnitude (V) | 5.07[2] |
| Characteristics | |
| Spectral type | A4m[3] |
| U−B color index | 0.190[2] |
| B−V color index | 0.146[2] |
| Astrometry | |
| Radial velocity (Rv) | +26.1±10.0[4] km/s |
| Proper motion (μ) | RA: +41.91[1] mas/yr Dec.: −66.88[1] mas/yr |
| Parallax (π) | 22.18±0.93 mas[1] |
| Distance | 147 ± 6 ly (45 ± 2 pc) |
| Absolute magnitude (MV) | 1.73[2] |
| Orbit[5] | |
| Primary | σ1 Tau A |
| Name | σ1 Tau B |
| Period (P) | 38.951 d |
| Eccentricity (e) | 0.15 |
| Longitude of the node (Ω) | 82° |
| Periastron epoch (T) | 2443094.319 JD |
| Semi-amplitude (K1) (primary) | 7.9 km/s |
| Details | |
| Mass | 1.94[2] M☉ |
| Luminosity | 14.7[6] L☉ |
| Surface gravity (log g) | 4.08[2] cgs |
| Temperature | 8,470[2] K |
| Rotational velocity (v sin i) | 56.5±7.1[7] km/s |
| Other designations | |
| 91 Tauri, BD+15°665, HD 29479, HIP 21673, HR 1478, SAO 94051, WDS J04393+1555B[8] | |
| Database references | |
| SIMBAD | data |
σ1 Tauri is a single-lined spectroscopic binary star system with an orbital period of 38.951 days and an eccentricity of 0.15. The visible component is an Am star with a stellar classification of A4m,[3] indicating it is chemically peculiar A-type star. It is spinning with a projected rotational velocity of 56.5 km/s.[7] The star has 1.9[2] times the mass of the Sun and is radiating 14.7[6] times the Sun's luminosity from its photosphere at an effective temperature of 8,470 K.[2] Although it lies in the general direction of the Hyades cluster, based on parallax measurements it has been excluded from the list of candidate members.[2]