[meteorite-list] Palomar Observes Broken Comet (Schwassmann-Wachmann 3)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon May 15 00:07:32 2006
Message-ID: <200605150358.UAA25265_at_zagami.jpl.nasa.gov>

http://pr.caltech.edu/media/Press_Releases/PR12851.html

Palomar Observes Broken Comet
Caltech News Release
May 12, 2006

PALOMAR MOUNTAIN, Calif.--Astronomers have recently been enjoying
front-row seats to a spectacular cometary show. Comet
73P/Schwassmann-Wachmann 3 is in the act of splitting apart as it passes
close to Earth. The breakup is providing a firsthand look at the death
of a comet.

Eran Ofek of the California Institute of Technology and Bidushi
Bhattacharya of Caltech's Spitzer Science Center have been observing the
comet's tragic tale with the Palomar Observatory's 200-inch Hale
Telescope. Their view is helping them and other scientists learn the
secrets of comets and why they break up.

The comet was discovered by Arnold Schwassmann and Arno Arthur Wachmann
76 years ago and it broke into four fragments just a decade ago. It has
since further split into dozens, if not hundreds, of pieces.

"We've learned that Schwassmann-Wachmann 3 presents a very dynamic
system, with many smaller fragments than previously thought," says
Bhattacharya. In all, 16 new fragments were discovered as a part of the
Palomar observations.

A sequence of images showing the piece of the comet known as fragment R
has been assembled into a movie. The movie shows the comet in the
foreground against distant stars and galaxies, which appear to streak
across the images. Because the comet was moving at a different rate
across the sky than the stellar background, the telescope was tracking
the comet's motion and not that of the stars. Fragment R and many
smaller fragments of the comet are visible as nearly stationary objects
in the movie.

"Seeing the many fragments was both an amazing and sobering experience,"
says a sleepy Eran Ofek, who has been working non-stop to produce these
images and a movie of the comet's fragments.

The images used to produce the movie were taken over a period of about
an hour and a half when the comet was approximately 17 million
kilometers (10.6 million miles) from Earth. Astronomically speaking the
comet is making a close approach to Earth this month giving astronomers
their front-row seat to the comet's break up. Closest approach for any
fragment of the comet occurs on May 12, when a fragment will be just 5.5
million miles from Earth. This is more than 20 times the distance to the
moon. There is no chance that the comet will hit Earth.

"It is very impressive that a telescope built more than 50 years ago
continues to contribute to forefront astrophysics, often working in
tandem with the latest space missions and biggest ground-based
facilities," remarks Shri Kulkarni, MacArthur Professor of Astronomy and
Planetary Science and director of the Caltech Optical Observatories.

The Palomar observations were coordinated with observations acquired
through the Spitzer Space Telescope, which imaged the comet's fragments
in the infrared. The infrared images, combined with the visible-light
images obtained using the Hale Telescope, will give astronomers a more
complete understanding of the comet's break up.

Additional support for the observations and data analysis came from
Caltech postdoc Arne Rau and grad student Alicia Soderberg.

Images of the comet and a time-lapse movie can be found at:

http://www.astro.caltech.edu/palomar/images/73p/

Contact:

Scott Kardel Palomar Public Affairs Director (760) 742-2111
wsk_at_astro.caltech.edu
Received on Sun 14 May 2006 11:58:12 PM PDT