A small asteroid is caught in the spin so fast that it discards material, according to new data from the space Hubble Space Telescope and other observatories.
The Hubble images show two narrow, comet-like shreds of dusty debris emanating from the asteroid (6478) Gault. Each queue is an episode in which the asteroid gently sheds its material – key evidence that Gault begins to decay.
Discovered in 1988, the 2.5-mile (4-mile) wide asteroid has been observed many times, but tail debris is the first evidence of degradation. Gault is 214 million miles (344 million kilometers) from the Sun. Of approximately 800,000 known asteroids between Mars and Jupiter, astronomers estimate that this type of event in the asteroid belt is a rare occurrence, which occurs approximately once a year.
Watching an asteroid allows astronomers to study the composition of these spaces.
"We did not have to go to Gault," explained Olivier Geno from the European Southern Observatory in Germany, a member of Gault's observation team. "We just had to look at the shredder image and see that all the grains of dust are well-sized. All large grains (around the size of the sand particles) are close to the object, and the smallest grains (the size of the grains of flour) are farthest away, as they are pushed as quickly as possible by the pressure of sunlight. only the second asteroid whose disintegration is strongly associated with a process known as the YORP effect. (YORP stands for "Yarkovski – Oh Kieff – Radzyevsky – Paddak", the names of four scientists who contributed to the concept.) When the sun's light heats up an asteroid, the infrared radiation coming out of its heated surface carries the angular impulse and the heat. This process creates a small torque that can make the asteroid rotate faster. When the resulting centrifugal force begins to overcome gravity, the surface of the asteroid becomes unstable, and the landslides can send dust and ruins to space a few miles an hour or the speed of a walking man. Researchers estimate that Gault can spin slowly over 100 million years.
Gault's collaborative work is an astronomical investigation involving telescopes and astronomers around the world. The research of all heavens, ground-based telescopes and space facilities like the Hubble Space Telescope have teamed up to make this discovery possible.
The initial trace was the accidental discovery of the first tail residue observed on January 5th. , 2019, from ATLAS telescope in Hawaii, funded by NASA. The queue also appears in archive data from December 2018 by ATLAS and the Panoramic Survey Telescope and the Pan-STARRS system in Hawaii. In mid-January, the second shorter queue was spied by the Canadian-France-Hawaii telescope in Hawaii and Isaac Newton's telescope in Spain, as well as other observers. Analysis of the two queues suggests that the two dust events occurred around October 28 and December 30, 2018.
Follow-up observations with the telescope William Herschel and the optical space station of the European Space Agency in La Palma and Tenerife, Spain and the Chimera Himalayan telescope in India measures the two-hour rotation of the object, near the critical speed at which a loose asteroid begins to decay a stack of pile. An example of a quick rotator of two hours, said team member Jan Clayna of Hawaii University in Honolulu.
Hubble's asteroid environment analysis shows no signs of widespread debris, which excludes the possibility of collision with another asteroid causing bursts. The narrow asteroid emitters suggest that the dust was released in short bursts, lasting from a few hours to a few days. These sudden events blew enough debris to make a "dirty ball" of about 500 feet (150 meters) if they were packed together. Tears will begin to disappear after a few months, when the dust is dispersed in the interplanetary space.
Based on the observations of the Canada-France-Hawaii telescope, astronomers estimate that the longer tail stretches more than half a million miles (800,000 km) and is approximately 4,000 miles (4,800 km) wide. The shorter tail is about a quarter.
So far only a few dozen active asteroids have been found. Now astronomers may have a chance to find much more of them because of improved observation capabilities of observatories like Pan-STARRS and ATLAS that scan the whole sky. "Asteroids like Gault can no longer escape," said Hino. "This means that all those asteroids that are starting to behave badly will be caught."
Researchers hope to watch Gault for more dust-related events.
The team's results were accepted for publication by The Astrophysical Journal Letters. Space Telescope is a project for international cooperation between NASA and ESA (European Space Agency). NASA's Space Flight Center in Greenbett, Maryland, operates the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble Research and Development. STScI is run by NASA from the Association of Astronomy Research Universities in Washington, DC
Paper: The Sporadic Activity of (6478) Gault: A YORP-Driven Event?