The space rock was flying within the Inner Asteroid Belt

Mar 6, 2014 16:09 GMT  ·  By
P/2013 R3 turned out to be a collection of at least 10 individual asteroid fragments in Hubble's eyes
   P/2013 R3 turned out to be a collection of at least 10 individual asteroid fragments in Hubble's eyes

Astronomers at the University of California in Los Angeles (UCLA) were recently able to use the NASA/ESA Hubble Space Telescope to monitor the breakup of an asteroid that was minding its own business inside the Inner Asteroid Belt (IAB), between the orbits of Mars and Jupiter. The space rock broke apart into at least 10 pieces as researchers were watching. 

Over the years, scientists have seen numerous celestial objects break apart as they were nearing the Sun. This is particularly true of comets, since only the largest and densest of them survive the fiery encounter with our parent star. However, the breakup of an asteroid has never been observed before.

The astronomical forensics investigation team was led by professor David Jewitt, who holds an appointment with the UCLA Department of Earth, Planetary and Space Sciences, and with the UCLA Department of Physics. Details of the study were published in the March 6 online issue of the esteemed Astrophysical Journal Letters.

The space rock was first detected by the Catalina and Pan-STARRS sky-survey telescopes, on September 15, 2013. From the get-go, the asteroid looked fuzzy and anomalous in shape, and experts soon caught on to the fact that it was crumbling. The rock has since been designated P/2013 R3.

About two weeks later, observation time was booked on the W. M. Keck Observatory, in Hawaii. Those measurements revealed the presence of three celestial bodies moving in tandem, at the very center of a dusty envelope that has a diameter roughly equal to Earth's. “The Keck telescope showed us that this asteroid was worth looking at with Hubble,” Jewitt explains.

Observations conducted with Hubble revealed that the three objects were in fact ten, each with its own dust tail. There are a total of four larger fragments, each measuring around 200 meters (650 feet) in diameter. These objects are moving away from each other as they are flying through space, at a speed of around 1.6 kilometers (1 mile) per hour.

P/2013 R3 most likely started coming apart sometime in early 2013, Jewitt and his group estimate. Due to the peculiar pattern the fragments are flying in, it is highly unlikely that a collision with another asteroid is to blame for its breakup, the team comments. The rocks now fly around 428.8 million kilometers (300 million miles) away from the Sun.

Early calculations indicate that the total weight of the flying mass of debris is somewhere around 200,000 tons. This implies that P/2013 R3 will in the distant future become a rich source of meteorites to fly within the inner solar system, and slam into the four rocky worlds orbiting closest to the Sun.