Comet Shoemaker–Levy 9

Comet Shoemaker–Levy 9

Comet Shoemaker–Levy 9 was discovered by Carolyn and Eugene M. Shoemaker and David Levy in 1993. It had been captured by Jupiter and was orbiting the planet at the time. The comet was later observed as a series of fragments ranging up to 2 km in diameter. These fragments collided with Jupiter’s southern hemisphere between July 16 and 22, 1994 at a speed of approximately 60 kms or 216,000 kmh.

About Comet Shoemaker–Levy 9 in brief

Summary Comet Shoemaker–Levy 9Comet Shoemaker–Levy 9 was discovered by Carolyn and Eugene M. Shoemaker and David Levy in 1993. It had been captured by Jupiter and was orbiting the planet at the time. The comet was later observed as a series of fragments ranging up to 2 km in diameter. These fragments collided with Jupiter’s southern hemisphere between July 16 and 22, 1994 at a speed of approximately 60 kms or 216,000 kmh. The collision provided new information about Jupiter and highlighted its possible role in reducing space debris in the inner Solar System. The prominent scars from the impacts were more easily visible than the Great Red Spot and persisted for many months. Its orbit around Jupiter was very loosely bound, with a period of about 2 years and an apoapsis of 0. 33 astronomical units. It is likely that it was captured from a solar orbit in the early 1970s, although the capture may have occurred as early as the mid-1960s. Because the comet’s motion with Jupiter was almost straight toward Jupiter, it ended up on a Jove-centric orbit of very high eccentricity. This is why it is very high up on the Jove’s Hill, which is said to be defined by Jupiter’s Hill sphere. Before the comet was captured, it was probably a short-period comet with an aphelion just inside Jupiter’s orbit, and a preihelion dating back to the asteroid belt. It was the ninth periodic comet discovered by the Shoemakers and Levy, hence its name.

The discovery was announced in IAU Circular 5725 on March 26, 1993, but its true nature was not recognised until the official announcement 5 days later. No images of the comet on a Schmidt photographic plate taken on March 19 were identified on March 21 by M. Lindgren, in a project searching for comets near Jupiter. Several other observers found images of SL9 in precovery images obtained before March 24, including Kin Endate from a photograph exposed on March 15, S. Otomo on March 17 and a team led by Eleanor Helin from images onMarch 19. The image of SL9 on March 24 was taken with the 0. 46 m Schmidt telescope at the Palomar Observatory in California. It appeared to show multiple nuclei in an elongated region about 50 arc seconds long and 10 arcseconds wide. Although the comet lay only about 4 degrees from Jupiter as seen from Earth, its apparent motion in the sky suggested that the comet is physically close to the planet. However, as his team were expecting comets to be inactive or at best exhibit a weak dust coma, and SL9 had a peculiar morphology, its true true nature wasn’t recognised until after March 24. It was their eleventh comet discovery overall including their discovery of two non-periodic comets, which use a different nomenclature. The discovery image gave the first hint that comet Shoemaker Levy 9 was an unusual comet.