Tau Tauri, Latinized from τ Tauri, is a quadruple star system[5] in the constellation Taurus. It is visible to the naked eye as a faint point of light with a combined apparent visual magnitude of 4.33.[14] The distance to this system is approximately about 400 light years based on parallax.[1] The system is moving further from the Earth with a heliocentric radial velocity of +14.6 km/s,[7] and it is a member of the Taurion OB association, located between Orion and Taurus.[15] It is located 0.7 degree north of the ecliptic, and thus is subject to lunar occultations.[4]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Taurus |
Right ascension | 04h 42m 14.70161s[1] |
Declination | 22° 57′ 24.9214″[1] |
Apparent magnitude (V) | 4.27[2] |
Characteristics | |
Spectral type | B3V[3] + ? + A0V–A2V[4] + A1V[5] |
U−B color index | -0.57[6] |
B−V color index | -0.14[6] |
Astrometry | |
Radial velocity (Rv) | +14.60[7] km/s |
Proper motion (μ) | RA: -2.89[1] mas/yr Dec.: -21.86[1] mas/yr |
Parallax (π) | 8.19 ± 0.88 mas[1] |
Distance | approx. 400 ly (approx. 120 pc) |
Absolute magnitude (MV) | -1.15[2] |
Orbit[8] | |
Primary | Aa |
Period (P) | 2.956549±0.000002 d |
Semi-major axis (a) | ≤ 0.01455 AU |
Eccentricity (e) | 0.051±0.019 |
Periastron epoch (T) | 2,436,424.207±0.009 JD |
Argument of periastron (ω) (secondary) | 126.7±21.8° |
Semi-amplitude (K1) (primary) | 53.6±1.0 km/s |
Details | |
Aa | |
Mass | 6.4[9] M☉ |
Luminosity | 1,472[10] L☉ |
Surface gravity (log g) | 2.60[11] cgs |
Temperature | 18,700[10] K |
Metallicity [Fe/H] | -0.51[11] dex |
Rotational velocity (v sin i) | 115[12] km/s |
Other designations | |
Database references | |
SIMBAD | data |
The blue-white hued primary, component Aa, is a B-type main-sequence star with a stellar classification of B3V.[3] It was found to be a close spectroscopic binary in 1903 by American astronomers Edwin B. Frost and Walter S. Adams. The pair have an orbital period of 2.96 days and eccentricity of 0.05.[8] A second companion, white-hued component Ab, has magnitude 6.97 and angular separation 0.2" from the primary in a 58-year orbit.[16][5] This is a probably A-type main-sequence star with a class of A0V–A2V.[4] The more distant component B is a type A1V star with magnitude 7.2 and separation 62.8".[5]
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