Castor (star) in their spectra, and all are flare stars. "α Geminorum" (Latinised to "Alpha Geminorum") is the star system's Bayer designation. Castor and Pollux are the two "heavenly twin" stars that give the constellation Gemini (meaning "twins" in Latin) its name. The name "Castor" refers specifically to Castor, one of the twin sons of Zeus and Leda in Greek and Roman mythology. The star was annotated by the Arabic description "Al-Ras al-Taum al-Muqadim", which translates as "the head of the foremost twin." In the catalogue of stars in the "Calendarium of Al Achsasi Al Mouakket", this star was designated "Aoul al
38 Leda of 116 ± 13 km. This is consistent with the asteroid dimensions computed through other means. Based upon a light curve that was generated from photometric observations of this asteroid at Pulkovo Observatory, it has a rotation period of 12.834 ± 0.001 hours and varies in brightness by 0.15 ± 0.01 in magnitude. 38 Leda Leda (; minor planet designation: 38 Leda) is a large, dark main-belt asteroid that was discovered by French astronomer J. Chacornac on January 12, 1856, and named after Leda, the mother of Helen of Troy in Greek mythology. In the Tholen classification system, it is