Hubble Witnesses Asteroid's Mysterious Disintegration
 
March 6, 2014: NASA's Hubble Space Telescope has recorded the ne
er-before-seen break-up of an asteroid into as many as 10 smaller pieces.
Fragile comets, comprised of ice and dust, have been seen falling apart as
they approach the sun, but nothing like this has ever before been observed in
the asteroid belt.
 
"This is a rock, and seeing it fall apart before our eyes is pretty amazing,"
said David Jewitt of the University of California at Los Angeles, who led the
astronomical forensics investigation.
 
The crumbling asteroid, designated P/2013 R3, was first noticed as an unusual,
fuzzy-looking object by the Catalina and Pan STARRS sky surveys on Sept. 15,
2013. A follow-up observation on October 1 with the W. M. Keck Observatory on
the summit of Mauna Kea, a dormant volcano on the island of Hawaii, revealed
three bodies moving together in an envelope of dust nearly the diameter of
Earth.
 
http://tinyurl.com/mr4x4jg
 
This series of Hubble Space Telescope images reveals the breakup of an
asteroid over a period of several months starting in late 2013. The largest
fragments are up to 180 meters (200 yards) in radius.  More
 
"The Keck Observatory showed us this thing was worth looking at with Hubble,"
Jewitt said. "With its superior resolution, space telescope observations soon
showed there were really 10 embedded objects, each with comet-like dust tails.
The four largest rocky fragments are up to 400 yards in diameter, about four
times the length of a football field."
 
Hubble data showed the fragments drifting away from each other at a leisurely
one mph.  The asteroid began coming apart early last year, but new pieces
continue to reveal themselves, as proved in the most recent images.
 
It is unlikely the asteroid is disintegrating because of a collision with
another asteroid, which would have been instantaneous and violent by
comparison to what has been observed. Debris from such a high-velocity smashup
would also be expected to travel much faster than observed. Nor is the
asteroid coming unglued due to the pressure of interior ices warming and
vaporizing.
 
This leaves a scenario in which the asteroid is disintegrating due to a subtle
effect of sunlight, which causes the rotation rate of the asteroid to
gradually increase. Eventually, its component pieces -- like grapes on a stem
-- succumb to centrifugal force and gently pull apart. The possibility of
disruption in this manner has been discussed by scientists for several years,
but never reliably observed.
 
For this scenario to occur, P/2013 R3 must have a weak, fractured interior --
probably as the result of numerous non-destructive collisions with other
asteroids. Most small asteroids are thought to have been severely damaged in
this way. P/2013 R3 is likely the byproduct of just such a collision sometime
in the last billion years.
 
With the previous discovery of an active asteroid spouting six tails, named
P/2013 P5, astronomers are finding more evidence the pressure of sunlight may
be the primary force causing the disintegration of small asteroids -- less
than a mile across-- in our solar system.
 
The asteroid's remnant debris, weighing about 200,000 tons, will in the future
provide a rich source of meteoroids. Most will eventually plunge into the sun,
but a small fraction of the debris may one day blaze across our skies as
meteors.
 
Credits:
Production editor: Dr. Tony Phillips | Credit: Science@NASA
 
More information:
 
The Hubble Space Telescope is a project of international cooperation between
NASA and the European Space Agency. NASA's Goddard Space Flight Center in
Greenbelt, Md., manages the telescope. The Space Telescope Science Institute
(STScI) in Baltimore conducts Hubble science operations. STScI is operated for
NASA by the Association of Universities for Research in Astronomy, Inc., in
Washington.
 
For images and more information about Hubble, visit:
 
http://www.nasa.gov/hubble
 
 
Regards,
 
Roger

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 * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)