巨蛇座 α (α Ser / α Serpentis)是在巨蛇座的一颗三合星系统，代表巨蛇的头。它的传统名称是Unukalhai，源自阿拉伯文的 عنق الحية；unuq al-ħayyah、"neck of the snake"，和由拉丁文翻译的Cor Serpentis："蛇的心脏"。巨蛇座 α是巨蛇座内最亮的恒星，与地球的距离大约是73.2光年。

主星，巨蛇座 αA，是一颗橘色的K-型巨星，视星等+2.63。它的总光度是太阳的70倍，表面温度4,300K，半径是太阳的15倍。巨蛇座 αB与主星相距58弧秒，星等+11.8等；巨蛇座 αC距离主星2.3弧分，星等+13等。

Alpha Serpentis (α Serpentis, α Ser) is a double star in the head (Serpens Caput) of the equatorial constellation Serpens. It has the traditional name Unukalhai. With an apparent visual magnitude of 2.6, this star is the brightest in the constellation and it can be viewed with the naked eye from most of the Earth. Parallax measurements yield an estimated distance of about 74 light-years (23 parsecs) from Earth.