尾宿九（υ Sco / υ Scorpii）是天蝎座的一颗恒星。其英文俗名Lesath（或者写作Leschath,Lesuth,Shaula,Al Juza,Alascha）来自阿拉伯语，意为“有毒动物的经过（或咬）”；但实际上这是Scaliger（一位懂阿拉伯语的欧洲天文学家）对“Alascha”的错译。Alascha来自阿拉伯语al laţkha ，意为“雾蒙蒙的小块”，即附近的疏散星团M7.

尾宿九距地球大约519光年。其光度大概是太阳的12,300倍，表面温度22,400开尔文。尾宿九半径是太阳的7.5倍，重量为太阳的10倍。由于质量巨大，尾宿九在其生命尽头会变成大质量的白矮星。

Upsilon Scorpii (υ Sco, υ Scorpii) is a star located in the "stinger" of the southern zodiac constellation of Scorpius, the scorpion. It has the traditional name Lesath (alternative spellings Leschath, Lesuth), from Arabic las'a = "pass (or bite) of a poisonous animal"; but this is a miscorrection by Scaliger (a European astronomer who knew Arabic) for earlier "Alascha", which came from Arabic al laţkha = "the foggy patch", referring to the nearby open cluster M7. On the night sky it lies near the 1.6 magnitude star Lambda Scorpii, so the two form an optical pair that is sometimes called the "Cat's Eyes".