March 6, 2014
Hubble Space Telescope Catches Asteroid Breaking Up Due To Sunlight
[ Watch the Video: The Breakup of Asteroid P/2013 R3 ]
Lee Rannals for redOrbit.com - Your Universe Online
Astronomers publishing a paper in the Astrophysical Journal Letters say they witnessed an asteroid breakup into as many as 10 smaller pieces. The team used NASA/ESA's Hubble Space Telescope to photograph the asteroid as it shredded when nearing the sun.
"Seeing this rock fall apart before our eyes is pretty amazing," David Jewitt, a professor in the UCLA Department of Earth, Planetary and Space Sciences and the UCLA Department of Physics and Astronomy, said in a statement.
Asteroid P/2013 R3 was first noticed on September 15, 2013 by the Catalina and Pan-STARRS sky-survey telescopes. Astronomers performed follow-up observations a few weeks later using the W.M. Keck Telescope on Hawaii's Mauna Kea. This survey revealed three co-moving bodies embedded in a dusty envelope that is nearly the diameter of Earth.
"The Keck telescope showed us that this asteroid was worth looking at with Hubble," Jewitt said.
The Hubble telescope helped reveal that there were 10 embedded objects, each with dust tails, within the asteroid. The four largest fragments are up to 200 yards in radius, or about twice the length of a football field.
Data revealed that the fragments are drifting apart from one another at a pace of about one mile per hour. The asteroid started falling apart last year, but new pieces have started emerging.
The scientists said it is unlikely the asteroid is breaking apart due to a collision with another asteroid because it is shedding its pieces slowly. They also said the asteroid isn’t coming apart due to the pressure of interior ices warming and vaporizing. P/2013 R3 is too cold for ices to significantly sublimate, and has maintained its 300-million-mile distance from the sun for a long time.
According to the astronomers, the asteroid is coming unglued because of a subtle effect of sunlight that causes the rotation rate to slowly increase. Jewitt said eventually, the asteroid will gently pull apart due to centrifugal force. In order for this scenario to have taken place, the asteroid must have a weak interior due to numerous ancient collisions with other asteroids.
Astronomers have been finding more circumstantial evidence that the pressure of sunlight may be the primary force that disintegrates small asteroids in the solar system. The Hubble recently discovered another active asteroid sprouting six tails due to pressure from sunlight.
"Hubble's incredible resolution and sensitivity are creating a new cottage industry for planetary scientists," Hal Weaver, of the Johns Hopkins University Applied Physics Laboratory in Laurel, Md., said in a statement.