Magnitude 5.27 | ||
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Tau1 Arietis (τ1 Ari, τ1 Arietis) is the Bayer designation for a triple star system in the northern constellation of Aries. Based upon an annual parallax shift of 6.41 mas, it is approximately 510 light-years (160 parsecs) distant from Earth. The combined apparent visual magnitude is 5.27, making it faintly visible to the naked eye.
The inner pair form an eclipsing binary system, with the brightness of the pair decreasing by 0.06 in magnitude during an eclipse of the primary. The third component is located at an angular separation of 0.810 arcseconds and has a magnitude of 8.17. The primary component is a subgiant star with a stellar classification of B5 IV. It has around 3.5 times the size of the Sun with five times the Sun's radius.
This system is a member of the Cas-Tau OB association of stars that share a common motion through space.