Hubble Confirms the World’s Largest Comet Nucleus

Hubble Confirms Largest Comet: The size of the largest ice comet nucleus ever seen by astronomers has been established thanks to NASA’s Hubble Space Telescope. It has an estimated diameter of 80 miles, making it bigger than the state of Rhode Island. The nucleus is roughly 50 times larger than the nuclei of the most well-known comets. It has a mass of 500 trillion tonnes, which is a hundred thousand times higher than that of a typical comet discovered much closer to the Sun.

C/2014 UN271 (Bernardinelli-Bernstein), a gigantic comet from the outside of the solar system, is barreling at us at 22,000 miles per hour. But don’t be concerned. It will never go closer to the Sun than 1 billion miles, which is somewhat more than the distance between Saturn and the Sun. And that won’t happen until 2031.

Comet C/2002 VQ94, with a nucleus estimated to measure 60 miles across, held the previous record. The Lincoln Near-Earth Asteroid Research (LINEAR) project detected it in 2002.

“This comet is literally the tip of the iceberg for many thousands of comets that are too faint to see in the more distant parts of the solar system,” said David Jewitt, a professor of planetary science and astronomy at UCLA and co-author of the new study published in The Astrophysical Journal Letters. “Because it is so bright at such a great distance, we’ve always assumed it must be a massive comet. We may now say with certainty that it is.”

In archived pictures from the Dark Energy Survey at the Cerro Tololo Inter-American Observatory in Chile, astronomers Pedro Bernardinelli and Gary Bernstein identified comet C/2014 UN271. It was initially discovered by chance in November 2010, when it was 3 billion miles from the Sun, or almost the typical distance to Neptune. It has been investigated extensively by terrestrial and space-based observatories since then.

Hubble to snap five photos of comet

“Given how active it is when it’s still so distant from the Sun,” said Man-To Hui of the Macau University of Science and Technology in Taipa, Macau, the paper’s lead author. “We had a feeling the comet would be quite large, but we needed the best data to be sure.” On January 8, 2022, his team utilized Hubble to snap five photos of the comet.

The difficulty in measuring this comet was distinguishing the solid nucleus from the massive dusty coma that surrounded it. Hubble can’t see the nucleus of the comet right now because it’s too far away. Instead, Hubble’s observations reveal a brilliant spike of light near the nucleus. Hui and his colleagues then created a computer model of the coma that was tweaked to fit the Hubble pictures. The coma’s glow was then removed, leaving the starlike nucleus remaining.

Hui and his colleagues matched the nucleus’ brightness to previous radio observations from Chile’s Atacama Large Millimeter/submillimeter Array (ALMA). The diameter and reflectivity of the nucleus are constrained by this combination of facts. The latest Hubble observations are in line with prior ALMA size estimates, but they strongly suggest a darker nucleus surface than previously anticipated. “It’s huge and blacker than coal,” Jewitt remarked.

For nearly a million years, the comet has been heading toward the Sun. It’s coming from the Oort Cloud, which is thought to be the home of trillions of comets. The inner border of the diffuse cloud is considered to be 2,000 to 5,000 times the distance between the Sun and the Earth. Its outer edge could extend at least a fourth of the way out to the Alpha Centauri system, which is the nearest star system to our Sun.

The comets of the Oort Cloud didn’t create so far from the Sun; rather, they were thrown out of the solar system billions of years ago by a gravitational “pinball game” between the huge outer planets, while Jupiter and Saturn’s orbits were still evolving. The far-flung comets only return to the Sun and planets when their distant orbits are disrupted by the gravitational attraction of a passing star, similar to apples falling from a tree.

Comet Bernardinelli-Bernstein has a 3-million-year-long elliptical orbit

Image Source: NASA 

Comet Bernardinelli-Bernstein has a 3-million-year-long elliptical orbit that takes it half a light-year from the Sun. The comet is currently fewer than 2 billion miles from the Sun, and it is practically perpendicular to our solar system’s plane. Temperatures are just about – 348 degrees Fahrenheit at that distance. Even yet, the temperature is high enough for carbon monoxide to sublimate off the surface, resulting in a dusty coma.

The size distribution of comets in the Oort Cloud, and thus its overall mass, is revealed by comet Bernardinelli-Bernstein. The mass of the Oort Cloud has been estimated to be up to 20 times that of Earth.

The Oort Cloud, first proposed in 1950 by Dutch astronomer Jan Oort, is still a theory because the many comets that make it up are too weak and far away to be directly witnessed. Ironically, this means that the greatest structure in the solar system is virtually unnoticeable. NASA’s Voyager spacecraft aren’t expected to reach the Oort Cloud’s inner region for another 300 years, and passing through it might take up to 30,000 years.

Infalling comets that can be traced back to this breeding area provide circumstantial proof. Because they approach the Sun from all sides, the cloud must be spherical in shape. These comets are deep-freeze samples of the early solar system’s material that have been preserved for billions of years. The existence of the Oort Cloud is supported by theoretical models of the solar system’s genesis and evolution. The more observational evidence astronomers can acquire through deep sky surveys and multiwavelength observations, the better they will be able to grasp the Oort Cloud’s involvement in the formation of the solar system.

NASA and the European Space Agency collaborated on the Hubble Space Telescope (European Space Agency). The telescope is managed by NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Hubble science operations are managed by the Space Telescope Science Institute (STScI) in Baltimore, Maryland. The Association of Universities for Research in Astronomy in Washington, D.C. manages STScI for NASA.

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