Comet Shoemaker–Levy 9 rarity: one post-impact study estimated that comets in diameter impact the planet once in approximately 500 years and those in diameter do so just once in every 6,000 years. There is very strong evidence that comets have previously been fragmented and collided with Jupiter and its satellites. During the Voyager missions to the planet, planetary scientists identified 13 crater chains on Callisto and three on Ganymede, the origin of which was initially a mystery. Crater chains seen on the Moon often radiate from large craters, and are thought to be caused by secondary impacts of the original ejecta, but the
4446 Carolyn The "Collaborative Asteroid Lightcurve Link" assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 32.03 kilometers based on an absolute magnitude of 11.2. This minor planet was named by the discoverer after American astronomer Carolyn Shoemaker (born 1929), a prolific discoverer of minor planets and comets, such as Comet Shoemaker–Levy 9. Many of her discoveries were co-discoveries with her husband Gene Shoemaker. The official naming citation was prepared by David Levy and Jean Mueller, and published by the Minor Planet Center on 27 June 1991 (). 4446 Carolyn 4446 Carolyn, provisional designation , is a