[meteorite-list] COMET HOLMES LONG LIVED?

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Fri, 26 Oct 2007 14:44:32 -0500
Message-ID: <03a401c81808$a2121c40$b92ee146_at_ATARIENGINE>

http://www.space.com/spacewatch/071026-comet-holmes-update.html

Dramatic Comet Outburst Could Last Weeks
By Robert Roy Britt
Senior Science Writer
posted: 26 October 2007
02:09 pm ET


A comet that suddenly brightened earlier this week
has astronomers around the globe fascinated. And
the show could go on for some time.

Comet Holmes, discovered in 1892, had in recent
years been visible only through telescopes until a
dramatic outburst made it visible to the naked eye.
In fewer than 24 hours, it brightened by a factor
of nearly 400,000.

It has now brightened by a factor of a million times
what it was before the outburst, a change "absolutely
unprecedented in the annals of cometary astronomy,"
said Joe Rao, SPACE.com's Skywatching Columnist.
The comet is now rivaling some of the brighter stars
in the sky. Anyone with a map should be able to spot
it now.

But Comet Holmes lacks a tail, so it's more like a fuzzy,
yellow star, observers report. The view is improved
with a small telescope.

"This is a terrific outburst," said Brian Marsden,
director emeritus of the Minor Planet Center, which
tracks known comets and asteroids. "And since
it doesn't have a tail right now, some observers
have confused it with a nova. We've had at least
two reports of a new star."

The comet could fade in a matter of days or weeks,
according to a statement from the Harvard-Smithsonian
Center for Astrophysics.

Comet expert John Bortle expects the comet to continue
as a naked-eye object for the next few weeks as it dims
gradually. Bortle said the coma, or fuzzy head of the
comet, could expand as weeks go by. The coma could
reach the apparent size of the moon in the sky, he said.

The comet is located among the stars of the constellation
Perseus, which is about halfway up in the northeast sky
in the evening. Perseus is almost directly overhead by
around 2 a.m. local daylight time and remains well up
in the northwest at dawn.

"The comet was plainly visible, disturbing the normal
pattern of stars that make up Perseus," Rao said after
observiing it last night.

The comet orbits the Sun once every seven years at
a distance of about 200 million miles (compared to
Earth's 93-million-mile orbit). It was re-observed in
1899 and 1906 before being lost for nearly six decades.
Based on a prediction by Marsden, the comet was
found again in 1964.

"Since then, it's been behaving well-until now,"
Marsden said. Astronomers don't know why the
outburst occurred.
Received on Fri 26 Oct 2007 03:44:32 PM PDT