136 Tauri
Star in the constellation Taurus
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136 Tauri is a white-hued binary star system in the zodiac constellation of Taurus. It has a combined apparent visual magnitude of 4.56,[2] which is bright enough to be faintly visible to the naked eye. Based upon an annual parallax shift of 7.71±0.22 mas as seen from Earth's orbit,[1] it is located approximately 420 light years from the Sun. The system is moving nearer with a heliocentric radial velocity of −17.2 km/s,[5] and is expected to make its closest approach in 6.5 million years at a distance of 150 ly (45 pc).[2]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Taurus |
| Right ascension | 05h 53m 19.64606s[1] |
| Declination | +27° 36′ 44.1378″[1] |
| Apparent magnitude (V) | 4.56[2] |
| Characteristics | |
| Spectral type | A0 V[3] (A0 V + A0 V)[2] |
| B−V color index | −0.008±0.009[2] |
| Variable type | suspected[4] |
| Astrometry | |
| Radial velocity (Rv) | −17.2±4.2[5] km/s |
| Proper motion (μ) | RA: +3.72[1] mas/yr Dec.: −10.11[1] mas/yr |
| Parallax (π) | 7.71±0.22 mas[1] |
| Distance | 420 ± 10 ly (130 ± 4 pc) |
| Absolute magnitude (MV) | −1.00[2] |
| Orbit[6] | |
| Period (P) | 5.969 d |
| Eccentricity (e) | 0.00 |
| Periastron epoch (T) | 2,420,147.25±10.0 JD |
| Argument of periastron (ω) (secondary) | 0.00° |
| Semi-amplitude (K1) (primary) | 48.9 km/s |
| Semi-amplitude (K2) (secondary) | 71.0 km/s |
| Details | |
| 136 Tau A | |
| Radius | 2.1[7] R☉ |
| Luminosity | 197.19[8] L☉ |
| Temperature | 8,732[8] K |
| Rotational velocity (v sin i) | 10[9] km/s |
| Other designations | |
| 136 Tau, BD+27°899, HD 39357, HIP 27830, HR 2034, SAO 77675[10] | |
| Database references | |
| SIMBAD | data |
This is a close, double-lined spectroscopic binary with an orbital period of 5.96 days and an eccentricity of 0.00.[6] Tidal effects between the pair may have circularized their orbit and slowed their rotation rates – the primary has a projected rotational velocity of 10 km/s.[9] They have a combined stellar classification of A0 V,[3] and both are most likely A-type main-sequence stars of the same class.[2]