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NASA's Hubble Telescope Witnesses Asteroid's Mysterious Disintegration
WASHINGTON, March 6, 2014 /PRNewswire-USNewswire/ -- NASA's Hubble
Space Telescope has recorded the never-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 near 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.
"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
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
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.
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:
/CONTACT: J.D. Harrington, Headquarters, Washington, 202-358-5241, email@example.com; Ray Villard, Space Science Telescope Institute, Baltimore, Md., 410-338-4493 / 410-338-4514, Villard@stsci.edu
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/Web Site: http://www.nasa.gov
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