Hale-Bopp, Comet

Comet discovered in 1994 by the amateur astronomers Alan Hale and Thomas Bopp at a distance from the Sun of about seven astronomical units, beyond Jupiter's orbit and farther than any comet detected before by amateurs.

Astronomers estimated its nucleus to be about 25 mi (40 km) in diameter, larger than most comets. At its closest approach to the Sun in April 1997, it was one of the intrinsically brightest comets in several centuries, though not the brightest as seen from Earth. The comet triggered the mass suicide near San Diego, Calif., U.S., in 1997 of 39 members of a religious cult known as Heaven's Gate, whose leader maintained that they would be reincarnated in a spacecraft following in the comet's wake.

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▪ astronomy

 long-period comet that was spectacularly visible to the naked eye, having a bright coma and a thick white dust tail. It was discovered independently in July 1995 by Alan Hale and Thomas Bopp, two American amateur astronomers, at the unusually far distance of 7 astronomical units (AU; about 1 billion km [600 million miles]) from the Sun, well beyond Jupiter's orbit. The comet reached perihelion (closest distance to the Sun) at 0.914 AU on April 1, 1997, without ever coming very close to Earth (nearest distance 1.31 AU), because its orbit was almost perpendicular to that of Earth. In addition to its broad dust tail, the comet possessed a narrower bluish plasma tail slanting away from the dust tail. From the comet's rate of gas production, its nucleus was estimated to be at least 30 km (20 miles) in diameter.

Armand H. Delsemme

 

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