139 Tauri
Star in the constellation Taurus
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139 Tauri is a single,[11] blue-white hued star in the zodiac constellation of Taurus. It is faintly visible to the naked eye with an apparent visual magnitude of 4.81.[2] The distance to this star, as determined from an annual parallax shift of 2.10±0.19 mas,[1] is roughly 1,600 light years. Because this star is located near the ecliptic, it is subject to occultations by the Moon. One such event was observed April 28, 1990.[12]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Taurus |
| Right ascension | 05h 57m 59.65632s[1] |
| Declination | +25° 57′ 14.0799″[1] |
| Apparent magnitude (V) | 4.81[2] |
| Characteristics | |
| Spectral type | B1 Ib[3][4] or B0.5 II[5] |
| B−V color index | −0.088±0.003[2] |
| Astrometry | |
| Radial velocity (Rv) | +8.0±4.2[6] km/s |
| Proper motion (μ) | RA: −2.06[1] mas/yr Dec.: −1.95[1] mas/yr |
| Parallax (π) | 2.10±0.19 mas[1] |
| Distance | 1,600 ± 100 ly (480 ± 40 pc) |
| Absolute magnitude (MV) | −4.4[7] |
| Details | |
| Mass | 10.1±1.0[3] M☉ |
| Radius | 20.7[8] R☉ |
| Luminosity | 81,000[8] L☉ |
| Surface gravity (log g) | 3.559±0.059[5] cgs |
| Temperature | 24,660±1,620[4] K |
| Rotational velocity (v sin i) | 140[9] km/s |
| Age | 22.5±2.6[3] Myr |
| Other designations | |
| 139 Tau, BD+25°1052, HD 40111, HIP 28237, HR 2084, SAO 77775[10] | |
| Database references | |
| SIMBAD | data |
This is a massive B-type lower-luminosity supergiant or bright giant star with a stellar classification of B1 Ib[3][4] or B0.5 II,[5] respectively. It is around 22.5[3] million years old with a high rate of spin, showing a projected rotational velocity of 140 km/s.[9] J. D. Rosendhal (1973) identified weak emission features associated with an asymmetric H-alpha absorption line, providing evidence of mass loss.[13] The star has about 10[3] times the mass of the Sun and around 20[8] times the Sun's radius. It is radiating over 80,000[8] times the Sun's luminosity from its photosphere at an effective temperature of around 24,660 K.[4] Stars such as this with 10 or more solar masses are expected to end their life by exploding as a Type II supernova.[14]