January 3, 2017

Our Sun may be tearing asteroids apart, study finds

A sun-grazing asteroid with a comet-like tail appears to be slowly breaking apart in space, and the sun may be to blame for its impending destruction, according to new research presented late last month at the Division of Planetary Sciences meeting in Pasadena, California.

The object in question is 3200 Phaethon, and according to NASA, it is technically classified as an asteroid – the first ever discovered via satellite, in fact. Discovered in 1983, it measures 5.10 kilometers (3.17 miles) in diameter and was later found to have a comet-like tail of debris.

Now, as reported on Friday, University of Western Ontario astronomer Paul Wiegert and his colleagues have found that the unusual object may be slowly breaking to pieces due to its close orbit to the sun, and that another object with a similar orbit could end up sharing its fate.

Wiegert’s team used the Canadian Meteor Orbit Radar (CMOR) to track objects one meter (3.3 feet) wide and smaller, and found that as Phaethon nears the sun, it appears to be breaking apart, only to reform again as it moves away. They likened it to a “slow motion” breakup.

Phaethon’s journey could be causing it to crumble to pieces

During its orbit, Phaethon comes closer to the sun than any other asteroid, and can even make it to half as far away as the orbit of Mercury (about 35 million miles), explained. Upon its exit, it makes it nearly as far away from the sun as Earth (93 million miles), ejecting materials which make up the Geminid meteor shower in the process.

Several years ago, researchers discovered that the asteroid had a tail of material similar to that of a comet – which itself is not uncommon, but in this case, the debris trail was not the result of any subsurface ice. Rather, Wiegert proposed that the trail of debris following Phaethon is caused by the path it travels around the sun causing it to slowly crumble into pieces.

science, asteroid, space, rock

As asteroids pass close to the sun, the rock slowly disintegrates, spreading dust and debris along its path (Credit: Karen Teramura, UH IfA.)

The study authors monitored Phaethon for several years, and found that asteroids this large tend to break up into surprisingly small pieces of debris, a fraction of an inch in size, that continue to orbit the sun. What this means is that such an asteroid could be slowly tearing itself apart while it orbits the sun, and begins to coalesce again once it begins to travel further out into space.

“It may be an asteroid going to the brink [of catastrophic breakup] and then retreating,” Wiegert told However, he emphasized that his team’s findings do not necessarily confirm the asteroid’s slow demise, and that the possibility remains that Phaethon behaves like a comet, with icy material from the surface forming its dust cloud.

They also found evidence that Comet 322P/SOHO 1 could also be experiencing a similar type of disruption, begging the question as to whether or not it actually is a comet. Research published in 2016 suggested that it could also be an asteroid, similar to Phaethon, in part because data appears to indicate that it is denser than any known comet and its activity is driven by a different series of processes than found in other comets.


Image credit: NASA/JPL-Caltech