String of Fragments Seen Trailing Comet

Hawaiian researchers have observed a “zoo” of at least 19 fragments strung out in a line behind Comet 57P/du Toit-Neujmin-Delporte. One or two companions to a comet are often seen, but 19 represent a very rare event. The fragments suggest the comet suffered a catastrophe, violent enough to break off pieces of its nucleus.

The event was most likely triggered by thermal stresses within the nucleus when it was warmed by sunlight. The pieces were observed with the University of Hawaii’s Mauna Kea telescope; the comet is too faint to be seen with the naked eye.

The string of fragments is spread out over 620,000 miles. Individual pieces probably range in size from a few hundred yards across to a few tens of yards across. The comet is named after the three astronomers who first discovered it. The 57P means it is the 57th comet on the list of those that have been observed on at least two of their passages around the sun. More information and a picture are available at www.ifa.hawaii.edu/~yan/57p.html.