Comet Bernardinelli Bernstein, also known as C/2014 UN271, is moving at about 22,000 miles per hour (35,400 km/h) in the approximate direction of Earth, although it never comes closer than 1 billion miles (1.6 billion km) from the sun meaning we would not be in harm way.
The nucleus is estimated to be about 80 miles (128.7 km) in diameter and have a mass of 500 trillion tons, making it about a hundred thousand times larger than the average comet closest to it, our Sun. The findings presented in a new study in The Astrophysical Journal Letters.
“This comet is literally the tip of iceberg for many thousands of comets that are too-faint to see in farthest parts of the solar system,” said David Jewitt, a professor at the University of California, Los Angeles (UCLA), and co- Author of new study. “We always suspected that this comet must be big because it’s so bright at such a great distance. Now we confirm that it is.
The previous record holder is C/2002 VQ94, which was estimated to be 60 miles (96.5 km) in diameter when it was discovered in 2002.
Stripping a comet down to its nucleus
Comet C/2014 UN27 was discovered by astronomers Pedro Bernardinelli & Gary Bernstein in November 2010 while examining archival images from the Dark Energy Survey at the Cerro Tololo Inter-American Observatory in Chile.
The team behind the new study set out to confirm predictions about Bernardinelli Bernstein’s immense size. They used the Hubble Space Telescope to take 5 photos of the comet on January 8, 2022. Using advanced computer modeling, they were able to measure the vast dusty coma enveloping . comet from comet nucleus.
“This is an amazing object considering how active it is, no matter how far from the Sun it is,” said study lead author Man-To Hui, of Macau University of Science and Technology, Taipa, Macau. “We assumed the comet could be quite large, but we needed the best data to confirm it.
To reach their findings, Hui & his team compared their data to previous radio observations from the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. The new data is close to previous data but suggests that Bernardinelli Bernstein has a much darker nucleus surface than previously thought.
The researchers believe their work provides valuable insight into Oort cloud, as the comet is thought to have originated from this theorized spherical layer of space rock that surrounds our solar system.
Since its launch in 1990, Hubble has made more than 1.5 million observations and counting, resulting in the publication of 18,000 scientific papers-on-papers ranging from dark energy to black holes & neutron stars. However, a series of technical problems over the past few months and years mean that the space observatory’s confirmation of the size of Bernardinelli Bernstein could be one of its final missions. It’s hard to predict exactly when Hubble will give way, and the iconic telescope still has some life left.