Castor and Pollux Castor and Pollux Castor and Pollux (or in Greek, Polydeuces) were twin half-brothers in Greek and Roman mythology, known together as the Dioscuri. Their mother was Leda, but they had different fathers; Castor was the mortal son of Tyndareus, the king of Sparta, while Pollux was the divine son of Zeus, who seduced Leda in the guise of a swan. Though accounts of their birth are varied, they are sometimes said to have been born from an egg, along with their twin sisters Helen of Troy and Clytemnestra. In Latin the twins are also known as the Gemini (literally "twins")
Pollux (star) is known as (, .) Parallax measurements made with the Hipparcos astrometry satellite place Pollux at a distance of about from the Sun. At an apparent visual magnitude of 1.14, Pollux is the brightest star in the constellation, brighter even than its neighbor Castor (Alpha Geminorum). The star is larger than the Sun, with about two times its mass and almost nine times its radius. Once an A-type main sequence star, Pollux has exhausted the hydrogen at its core and evolved into a giant star with a stellar classification of K0 III. The effective temperature of this star's outer envelope