Quasi-Hilda comet comet: 39P/Oterma was a quasi-Hilda before a close approach to Jupiter in 1963. 77P/Longmore falls outside of the bulk distribution because of its large eccentricity and inclination. Comet Shoemaker–Levy 9 impacted with Jupiter in 1994. Quasi-Hilda comet A quasi-Hilda comet (QHC) is a Jupiter-family comet that interacts strongly with Jupiter and undergoes extended temporary capture by it. These comets are associated with the Hilda asteroid zone in the 3:2 inner mean-motion resonance with Jupiter. Typically, asteroids in this zone have a semimajor axis between 3.70 and 4.20 AU, eccentricities below 0.30, and inclinations of no more than 20°. Comets can
Comet Shoemaker–Levy 9 Despite published predictions, astronomers had not expected to see the fireballs from the impacts and did not have any idea in advance how visible the other atmospheric effects of the impacts would be from Earth. Observers soon saw a huge dark spot after the first impact. The spot was visible even in very small telescopes, and was about (one Earth radius) across. This and subsequent dark spots were thought to have been caused by debris from the impacts, and were markedly asymmetric, forming crescent shapes in front of the direction of impact. Over the next six days, 21 distinct impacts