Comet Tempel-Tuttle, also known as 55P/Tempel–Tuttle, is a Halley-type comet with a 33-year orbital period. It was discovered by Wilhelm Tempel and Horace Parnell Tuttle in 1865 and 1993. The comet was the first active comet observed orbiting a planet, likely captured by Jupiter around 20-30 years earlier. Its unusual fragmented form was due to a closer approach to Jupiter in 1992, which caused it to collide with Jupiter's southern hemisphere between July 16 and 22, 1994.