dipper@utastro.UUCP (Debbie Byrd) (12/12/85)
The parent comet for the Geminid meteor shower is a very mysterious object. More -- after this. December 12 Phaethon We're close to the peak of the Geminid meteor shower, one of the best of the year. The peak is around midnight tomorrow night. But -- if you're looking in a very dark sky -- you might see some Geminids tonight, too, as the shower builds toward maximum. We see meteors as streaks of light in our night sky. They're sometimes called "shooting stars." Those streaks usually originate as bits of debris left behind in space by comets. Many meteor showers have known parent comets. For example, the Orionid shower in October stems from Comet Halley. But the parent comet of the Geminids was unknown -- until a candidate object was found in 1983. The Infrared Astronomical Satellite, IRAS, discovered an object first called 1983TB -- and later named 3200 Phaethon, for the mythical son of Helios, the sun god. This object moves in an orbit that's very similar to that of the Geminid meteor stream. It appears to be the object that spawned the meteors. But astronomers don't know whether to call Phaethon an asteroid or a dead comet. Though it orbits very close to the sun, it doesn't have a tail or surrounding gas cloud -- which most comets develop near the sun. Phaethon may be a dead comet -- with its ability to form a tail gone. But studies show that it appears to be more like an asteroid. If so, then it's hard to explain how an asteroid spawned the Geminid meteors -- which are rich in number and very regular year after year. Did some other object collide with Phaethon -- and break off the Geminid meteors? For now, no one knows. Script by Deborah Byrd. (c) Copyright 1984, 1985 McDonald Observatory, University of Texas at Austin