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Comet C/2014 UN271 Nucleus

Three panels with image of comet, a model, and a subtracted version just showing the nucleus of the fuzzy blue blob

This sequence shows how the nucleus of Comet C/2014 UN271 (Bernardinelli-Bernstein) was isolated from a vast shell of dust and gas surrounding the solid icy nucleus. On the left is a photo of the comet taken by the NASA Hubble Space Telescope's Wide Field Camera 3 on January 8, 2022. A model of the coma (middle panel) was obtained by means of fitting the surface brightness profile assembled from the observed image on the left. This allowed for the coma to be subtracted, unveiling the point-like glow from the nucleus. Combined with radio telescope data, astronomers arrived at a precise measurement of the nucleus size. That's no small feat from something about 2 billion miles away. Though the nucleus is estimated to be as large as 85 miles across, it is so far away it cannot be resolved by Hubble. Its size is derived from its reflectivity as measured by Hubble. The nucleus is estimated to be as black as charcoal. The nucleus area is gleaned from radio observations.

About the Object

Distance
DistanceThe physical distance from Earth to the astronomical object. Distances within our solar system are usually measured in Astronomical Units (AU). Distances between stars are usually measured in light-years. Interstellar distances can also be measured in parsecs.
At the time of observations, the comet was about 19 AU from Earth (2 billion miles).

About the Data

Data Description
Data DescriptionProposal: A description of the observations, their scientific justification, and the links to the data available in the science archive.
Science Team: The astronomers who planned the observations and analyzed the data. "PI" refers to the Principal Investigator.
HST observations include those from programs 16886 (M. Hui).
Instrument
InstrumentThe science instrument used to produce the data.
WFC3/UVIS
Exposure Dates
Exposure DatesThe date(s) that the telescope made its observations and the total exposure time.
8 Jan 2022
Filters
FiltersThe camera filters that were used in the science observations.
F350LP

Object Name
Object NameA name or catalog number that astronomers use to identify an astronomical object.
Comet C/2014 UN271
Object Description
Object DescriptionThe type of astronomical object.
Large Oort cloud comet
Release Date
April 12, 2022
Science Release
Hubble Confirms Largest Comet Nucleus Ever Seen
Read the release
Credits
NASA, ESA, Man-To Hui (Macau University of Science and Technology), David Jewitt (UCLA); Image Processing: Alyssa Pagan (STScI)

Downloads

Full Res, 1080 × 360
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This image is an exposure acquired by the WFC3 instrument on the Hubble Space Telescope. The color results from assigning the color blue to a monochromatic (grayscale) image.

Related Images & Videos

Comparison of Comet Nucleus Sizes

This diagram compares the size of the icy, solid nucleus of comet C/2014 UN271 (Bernardinelli-Bernstein) to several other comets. The majority of comet nuclei observed are smaller than Halley’s comet. They are typically a mile across or less. Comet C/2014 UN271 is currently the...