Zeta Arietis

Zeta Arietis, Latinized from ζ Arietis, is a star in the northern constellation of Aries. It is dimly visible to the naked eye with an apparent visual magnitude of +4.89. Based upon an annual parallax shift of 12.77 mas, the distance to this star is 255 ±. This is an A-type main sequence star with a stellar classification of A1 V. It has a high rate of rotation with a projected rotational velocity of 133 km/s. The star is shining at an effective temperature of 9,500 K, giving it the characteristic white-hued glow of an A-type star.

Name
This star, along with δ Ari, ε Ari, π Ari, and ρ3 Ari, were Al Bīrūnī's Al Buṭain (ألبطين), the dual of Al Baṭn, the Belly. According to the catalogue of stars in the Technical Memorandum 33-507 - A Reduced Star Catalog Containing 537 Named Stars, Al Buṭain were the title for five stars : δ Ari as Botein, π Ari as Al Buṭain I, ρ3 Ari as Al Buṭain II, ε Ari as Al Buṭain III dan ζ Ari as Al Buṭain IV.

In Chinese, 天陰 (Tiān Yīn), meaning Yin Force, refers to an asterism consisting of ζ Arietis, 63 Arietis, δ Arietis, τ Arietis and 65 Arietis. Consequently, the Chinese name for ζ Arietis itself is 天陰二 (Lóu Su èr, the Second Star of Yin Force.)