Τ_Tauri
Tau Tauri
Star system in the constellation Taurus
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]
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]