UMD astronomers discovered that comet Bernardinelli-Bernstein is among
the most distant active comets from the sun, providing key information about its composition.
© NOIRLab/NSF/AURA/J. da Silva/SpaceengineThe Comet Bernardinelli-Bernstein (BB), represented in this artist rendition as it might look in the outer Solar System, is estimated to be about 1000 times more massive than a typical comet. The largest comet discovered in modern times, it is among the most distant comets to be discovered with a coma, which means ice within the comet is vaporizing and forming an envelope of dust and vapor around the comet’s core.
A new study by University of Maryland astronomers shows that comet Bernardinelli-Bernstein (BB),
the largest comet ever discovered, was active long before previously thought, meaning the ice within it is vaporizing and forming an envelope of dust and vapor known as a coma. Only one active comet has been observed farther from the sun, and it was much smaller than comet BB.
The finding will help astronomers determine what BB is made of and provide insight into conditions during the formation of our solar system. The finding was published in
The Planetary Science Journal on November 29, 2021.
"These observations are pushing the distances for active comets dramatically farther than we have previously known," said
Tony Farnham, a research scientist in the UMD
Department of Astronomy and the lead author of the study.
Knowing when a comet becomes active is key to understanding what it's made of. Often called "dirty snowballs" or "icy dirtballs," comets are conglomerations of dust and ice left over from the formation of the solar system. As an orbiting comet approaches its closest point to the sun, it warms, and the ices begin to vaporize. How warm it must be to start vaporizing depends on what kind of ice it contains (e.g., water, carbon dioxide, carbon monoxide or some other frozen compound).
