Images captured by the Hubble Space Telescope in January and released by NASA last week provide the best look yet at a disintegrating comet, showing in great detail how solar radiation was ultimately responsible for the demise of the 4.5-billion-year-old object.
According to Space.com and Motherboard, the photographs were taken over a three-day span when the 1,600-foot-long comet known as 332P/Ikeya-Murakami or Comet 332P was roughly 150 million miles from the sun, or approximately the same distance away as planet Mars.
The images show the core being trailed by several bluish-white specks, and as the 332P (which is made from ice and dust) travels along its path, the sun’s rays cause it to begin breaking apart, and in later images, 25 building-sized fragments are clearly shown drifting away from the comet.
The observations “suggest that” the comet “may be spinning so fast that material is ejected from its surface,” NASA explained. The debris that resulted “is now scattered along a 3,000-mile-long trail, larger than the width of the continental US,” the agency noted. “These observations provide insight into the volatile behavior of comets as they approach the sun and begin to vaporize.”
A paper detailing the findings has been published in Astrophysical Journal Letters.
Comet appears to be ‘fragmenting itself into oblivion’
Believed to be nearly as old as the solar system itself, Comet 332P was originally discovered in November 2010 by Japanese astronomers Kaoru Ikeya and Shigeki Murakami. For most of its lifespan, the comet remained in the Kuiper Belt, but a fateful encounter with Neptune caused the comet to slingshot towards the planets and the sun, according to Motherboard.
The new images show that the comet fragments alternately become brighter or darker as the icy patches on their surface rotate into or out of sunlight, NASA explained. Also, these observations show that the shards (which make up about 4% of the comet and are between 65-200 feet wide) change shape and move away from each other at speeds of just a few miles per hour. The comet itself also changes brightness on a cycle of between two and four hours, the agency said.
So what exactly is happening to the comet? Based on the Hubble data, researchers believe that when the sun heats 332P, it causes eruptions of dust and gas from its surface. These jets cause the rotation of the comet to increase due to its small nucleus, and the increased rate of spin causes chunks of matter to essentially fall off the comet and drift off into space.
“We know that comets sometimes disintegrate, but we don’t know much about why or how they come apart,” lead researcher David Jewitt from UCLA said in a statement. “The trouble is that it happens quickly and without warning, and so we don’t have much chance to get useful data.” He added that Hubble’s “fantastic resolution” allowed his team to monitor small, faint fragments of the comet and watch them as they change from one day to the next.
“That has allowed us to make the best measurements ever obtained on such an object,” he added. “In the past, astronomers thought that comets die when they are warmed by sunlight, causing their ices to simply vaporize away. Either nothing would be left over or there would be a dead hulk of material where an active comet used to be. But it’s starting to look like fragmentation may be more important. In Comet 332P we may be seeing a comet fragmenting itself into oblivion.”
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Image credit: NASA/ESA
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