Showy comet lives up to its billing.
"This is the first time we've had a comet with a lot of notice that really did live up to expectations, "says Brian G. Marsden of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. Hale-Bopp's closest approach to the sun, on April 1, sped the melting of the comet's nucleus, making the tail longer and wider. The comet should remain bright for a few weeks, but the waxing moon may obstruct the view, Marsden said.
While Hale-Bopp's fiery performance unfolds, astronomers are compiling an inventory of its ingredients. The list consists mainly of common molecules like water and carbon dioxide, but it includes some never before detected in a comet, says Harold A. Weaver of Johns Hopkins University in Baltimore. These molecules--formic acid, sulfur dioxide, cyanoacetylene, [H.sub.2]CS--and new isotopes of hydrogen cyanide and carbon monosulfide may have existed in other comets but in such tiny proportions that they were hidden behind more abundant ones. "You need a very bright comet like Hale-Bopp to detect them, "says Weaver.
The comet's next appearance is tentatively scheduled for 4397.
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|Title Annotation:||Hale-Bopp comet|
|Article Type:||Brief Article|
|Date:||Apr 12, 1997|
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