The Hubble Space Telescope measured that the nucleus of the largest comet ever seen in the Solar System, C / 2014 UN271 (Bernardinelli – Bernstein), is 129 kilometers wide.
The comet was first detected in 2014 by the Dark Energy Survey (DES), conducted by NOIRLabThe Victor M. Blanco Telescope at the Cerro Tololo Inter-American Observatory in Chile, but not until 2021 did University of Pennsylvania astronomers Pedro Bernardinelli and Gary Bernstein find the comet while screening for the amount of data collected by DES.
The comet is very far from the Sun and is now between the orbits of Uranus and Neptune, at a distance of less than three billion kilometers. The closest to the Sun. – what astronomers call a perihelion – about 1.6 billion kilometers, is outside Saturn’s orbit, by 2031. It will not threaten Earth.
“We always thought this comet was big because it was the brightest thing at a distance, “said David Jewitt of the University of California, Los Angeles.” Now we’re confirmed. “
Jewitt is part of a group led by Man-To Company of the Macau University of Science and Technology that used Hubble on January 8, 2022 to photograph. Bernardinelli–Bernstein. However, Hubble was unable to separate the comet’s nucleus from its gaseous coma at great distances. A coma is the result of action on and near the comet’s surface as it is slowly warmed by the Sun. Therefore, the team used a computer method to describe the expected size and nature of the coma at its current distance, relative to the comet’s temperature (-211 degrees Celsius), Which is the temperature for carbon monoxide ice to sublimate to create a coma. They then extracted the model from the Hubble images. The star -like point that is deposited is the solid nucleus of the comet. From its brightness, and from comparisons with radio-wavelong observations by the Atacama Large Millimeter / submillimeter Array (ALMA) in Chile, they were able to judge how much light a comet reflected, and then due to him and the brightness of the comet. to calculate the diameter of its nucleus.
They knew it was a cometThe skin doesn’t care. “It’s darker than coal,” Jewitt said. That is, in order to receive the amount of light it receives, the comet’s nucleus must be greater than the predicted 100 kilometers, in order to accurately reflect the light.
The cometIt has the same diameter as a small moon, but where did this large comet come from? Astronomers believe that there is a large cloud of ice bodies at the far end of the Solar System, possibly extending a light year from the Sun. They call this the Oort Cloud. Sometimes some of these bodies of ice could be released from their orbits, perhaps because of the gravity of the moving star, and begin to fall on the Sun. Comet Bernardinelli–BernsteinHe began his journey in this way more than a million years ago and is now very close.