Don Savage
Headquarters, Washington, DC              October 11, 1995
(Phone:  202/358-1547)

Jim Sahli
Goddard Space Flight Center, Greenbelt, MD
(Phone:  301/286-0697)

Ray Villard
Space Telescope Science Institute, Baltimore, MD
(Phone:  410/338-4514)

RELEASE:  95-178

HUBBLE SEES MATERIAL EJECTED FROM COMET HALE-BOPP

       New pictures from NASA's Hubble Space Telescope of the
recently discovered comet Hale-Bopp show a remarkable spiral
"pinwheel" pattern and a "blob" of free-flying debris near the
comet's nucleus.

       Although this comet is still well outside the orbit of
Jupiter (almost 600 million miles from Earth) it looks
surprisingly bright, fueling predictions that it could become
the brightest comet of the century in early 1997.  The Hubble
observations will help scientists determine if Hale-Bopp is
really a giant comet or rather a more moderate-sized object
whose current activity is driven by outgassing from very
volatile ice which will "burn out" over the next year.

       The bright clump of light along the spiral may be a
piece of the comet's icy crust that was ejected into space by
a combination of ice evaporation and the comet's rotation,
which then disintegrated into a visible cloud of particles.

       Although the ejected "blob" is  about 3.5 times fainter
than the brightest portion of the nucleus, the clump appears
brighter because it covers a larger area.  The debris follows
a spiral pattern because the solid nucleus is rotating like a
lawn sprinkler, completing a single rotation about once per week.

       Ground-based observations conducted over the past two
months have documented at least two separate episodes of jet
and pinwheel formation and fading.  By coincidence, the first
Hubble images of Hale-Bopp, taken Sept. 26, immediately
followed one of these outbursts and allow researchers to
examine it at unprecedented detail.  For the first time, they
saw a clear separation between the nucleus and some of the
debris being shed.

       By putting together information from the Hubble images
and those taken during the recent outburst using a telescope
at the Teide Observatory (Tenerife, Canary Islands, Spain),
astronomers found that the debris is moving away from the
nucleus at a speed of about 68 miles per hour.

       Even more detailed Hubble images will be taken with the
Planetary Camera in late October to follow the further
evolution of the spiral, look for more outbursts, place limits
on the size of the nucleus, and use spectroscopy to study the
enigmatic comet's chemical composition.

       Comet Hale-Bopp was discovered on July 23, 1995, by
amateur astronomers Alan Hale and Thomas Bopp.  The Space
Telescope Science Institute is operated by the Association of
Universities for Research in Astronomy, Inc. (AURA) for NASA,
under contract with the Goddard Space Flight Center, Greenbelt,
MD.  The Hubble Space Telescope is a project of international
cooperation between NASA and the European Space Agency (ESA).

                    - end -

EDITOR'S NOTE:  An image of Hale-Bopp is available to media
representatives by calling the Headquarters Imaging branch at
202/358-1900.  NASA photo number is:    color:  95-HC-607
                                          B&W:  95-H-618

Image files in GIF and JPEG format may be accessed on the
Internet via anonymous ftp from ftp.stsci.edu in /pubinfo. The
same images are available via World Wide Web from URL
http://www.stsci.edu/pubinfo/Latest.html, or via links in
http://www.stsci.edu/pubinfo/Pictures.html

PRC95-41  Comet Hale-Bopp

gif/HaleBopp.gif

jpeg/HaleBopp.jpg


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