Sigma1 Tauri
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Taurus |
| Right ascension | 04h 39m 09.22247s |
| Declination | +15° 47′ 59.5345″ |
| Apparent magnitude (V) | 5.07 |
| Characteristics | |
| Spectral type | A4m |
| U−B color index | 0.190 |
| B−V color index | 0.146 |
| Astrometry | |
| Radial velocity (Rv) | +26.1±10.0 km/s |
| Proper motion (μ) | RA: +41.91 mas/yr Dec.: −66.88 mas/yr |
| Parallax (π) | 22.18±0.93 mas |
| Distance | 147 ± 6 ly (45 ± 2 pc) |
| Absolute magnitude (MV) | 1.73 |
| Orbit | |
| 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 M☉ |
| Luminosity | 14.7 L☉ |
| Surface gravity (log g) | 4.08 cgs |
| Temperature | 8,470 K |
| Rotational velocity (v sin i) | 56.5±7.1 km/s |
| Other designations | |
| 91 Tauri, BD+15°665, HD 29479, HIP 21673, HR 1478, SAO 94051, WDS J04393+1555B | |
| Database references | |
| SIMBAD | data |
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, which indicates it is visible to the naked eye. Based upon parallax measurements, σ1 Tauri is about 147 light-years from the Sun.
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, indicating it is chemically peculiar A-type star. It is spinning with a projected rotational velocity of 56.5 km/s. The star has 1.9 times the mass of the Sun and is radiating 14.7 times the Sun's luminosity from its photosphere at an effective temperature of 8,470 K. 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.