IKEYA-SEKI, COMET

one of a group of Sun-grazing comets having similar orbits and including the great comet known as 1882 II. Discovered Sept. 18, 1965, by two Japanese amateur astronomers, Ikeya Kaoru and Seki Tsutomu, Ikeya-Seki made its closest approach to the Sun (470,000 kilometres, or about 290,000 miles; less than the Sun's radius) on Oct. 21, 1965. The comet was then bright enough to be seen with the naked eye in daylight. Like the similarly spectacular Comet 1882 II, it was fragmented by its proximity to the Sun; Ikeya-Seki gave astronomers their first chance since 1882 to study a comet in such conditions.