Zdenek Sekanina Zdenek Sekanina Zdenek Sekanina (born 12 June 1936, Mladá Boleslav, Czechoslovakia (now Czech Republic)) is a Czech-American astronomer and scientist. In 1959, Sekanina started to study astronomy at Charles University in Prague, where he was graduated in 1963. Since 1980, he has been working at the Jet Propulsion Laboratory. His main areas of professional study are meteors and interplanetary dust as well as the study of comets. In the course of his investigations, he dealt with Halley's comet, the Tunguska event, as well as the break-up and impact of Comet Shoemaker–Levy 9 on Jupiter. He was involved in the data
Comet Shoemaker–Levy 9 thus a serendipitous discovery, but one that quickly overshadowed the results from their main observing program. Comet Shoemaker–Levy 9 was the ninth periodic comet (a comet whose orbital period is 200 years or less) discovered by the Shoemakers and Levy, hence its name. It was their eleventh comet discovery overall including their discovery of two non-periodic comets, which use a different nomenclature. The discovery was announced in IAU Circular 5725 on March 27, 1993. The discovery image gave the first hint that comet Shoemaker–Levy 9 was an unusual comet, as it appeared to show multiple nuclei in an elongated region