A mysterious trail of debris spotted by the Hubble Space Telescope suggests two asteroids recently collided, NASA said Feb. 2 in a press release.
Though astronomers believe such collisions to be common, NASA says the X-shaped debris pattern observed by Hubble Jan. 25 and Jan. 29 marks the first time direct evidence of the cosmic smashups has been recorded. The pictures released Feb. 2 show a comet-like object, dubbed P/2010 A2, with an X-pattern of filamentary structures near the nucleus.
“This is quite different from the smooth dust envelopes of normal comets,” said astronomer David Jewitt of the University of California at Los Angeles. “The filaments are made of dust and gravel, presumably recently thrown out of the nucleus. Some are swept back by radiation pressure from sunlight to create straight dust streaks. Embedded filaments are co-moving blobs of dust that likely originated from tiny unseen parent bodies.”
The images were captured by Hubble’s Wide Field Camera 3, which was installed during the May 2009 space shuttle servicing mission.
NASA said the two asteroids likely smashed into each other with an average impact speed of more than 17,000 kilometers per hour.
The Hubble photos show that the main nucleus of P/2010 A2 lies outside its own halo of dust. This pattern has never been seen before in a comet-like object. The nucleus is estimated to be about 140 meters in diameter.
Scientists think this nucleus is the surviving remnant of the collision, and the tail is the rubble left over from the crash.
“If this interpretation is correct, two small and previously unknown asteroids recently collided, creating a show of debris that is being swept back into a tail from the collision site by the pressure of sunlight,” Jewitt said.
P/2010 A2 orbits in the warm, inner regions of the asteroid belt between Mars and Jupiter. When the object was observed, it was approximately 290 million kilometers from the sun and 145 million kilometers from Earth, NASA said in the release.