Hubble Confirms Comet C/2014 UN271 is an Absolute Unit, Astronomically Speaking

It's official. The largest nucleus ever seen in a comet is seen in comet C/2014 UN271. The Hubble Space Telescope was used to determine the exact size of the comet after it was discovered in the fall of 2021.

NASA said a team of scientists has determined that the diameter is more than the state of Rhode Island. The nucleus is 50 times larger than other comets. Its mass is 500 trillion tons, a hundred thousand times greater than a comet found closer to the Sun.

The object is so active that it is still so far from the Sun.

Pedro Bernardinelli and Gary Bernstein discovered the comet. They were looking at the data from the Dark Energy Camera on the 4-meter Telescope. The object was thought to be a dwarf planet because it did not show a typical comet tail.

Astronomers using the Las Cumbres Observatory network took new images which showed that it has grown coma in the past 3 years and is moving quickly through the Oort Cloud. The object was classified as a comet.

Astronomers began studying this comet in earnest, taking data from all sorts of previous and recent observational sources.

It will never get closer to the Sun than it is now, because it is moving in the direction of the Sun from the outer Solar System. It won't be until the year 2031. It won't be visible to the naked eye, but only large telescopes will be able to see it.

The comet has a challenge in trying to measure the nucleus while it is in a coma. While the comet is too far away for Hubble to see its nucleus, the data shows a bright spike of light at its location. The computer model of the coma was adjusted to fit the Hubble images. The coma's glow was removed to leave behind a starlike nucleus.

The measurement of the coma is close to the estimates of 100 to 200 km, thanks to the work of Hui and his team. The nucleus was described as blacker than coal.

The largest comet ever measured was C/2002 VQ94, with a nucleus estimated to be 60 miles across. It was discovered in 2002 by the Lincoln Near-Earth Asteroid Research project.

There are more comets like this, with their origins at the edge of the Solar System.

David Jewitt is a professor of planetary science and astronomy at the University. We confirm that it is.

The lead image caption is:

The size of the comet's nucleus is compared to several other comets. The majority of comet nuclei are small. They are usually a mile across. The record for big comets is currently held by C/2014 UN271. It may be just the beginning. As sky surveys improve in sensitivity, there could be many more monsters out there. The Hubble Space Telescope has the sharpness and sensitivity to make a definitive estimate of nucleus size, even though the comet must be big to be detected so far out to a distance of over 2 billion miles from Earth.

There is a NASA press release and a paper in the Astrophysical Journal.