- Bernardinelli-Bernstein is one of the most distant active comets from the Sun.
- The ice within it is evaporating and forming a coma – an envelope of dust and vapor
- At 62 miles (100 km) across, Comet BB is the largest comet ever discovered
A new study claims that ‘megacomet’ Bernardinelli-Bernstein – a giant iceball 100 times larger than a normal comet – is one of the most distant ice balls with an active stream of dust and gas.
Astronomers have analyzed satellite images of the comet, also known as C/2014 UN271, which was identified earlier this year.
Active comets such as Bernardinelli-Bernstein (BB) develop a thin envelope of vaporized ice and dust around it, known as a coma, as they approach the Sun.
Bibi’s vaporized ice is not water, but carbon monoxide, which researchers have found, known for its ability to deadly poison humans on Earth.
Comet Bernardinelli-Bernstein (BB), represented in this artist’s presentation as it might appear in the outer Solar System, is estimated to be about 100 times larger than a typical comet. The largest comet discovered in modern times, it is one of the most distant comets discovered with a coma, which means that the ice within the comet is evaporating and a mass of dust and vapor surrounds the comet’s core. Making envelopes.
Bernardinelli–Bernstein (BB) or C/2014 UN271 is a comet in the outer Solar System.
It was identified as a comet earlier this year from images originally captured in 2014.
At 62 miles (100 km) across, it has been described as the largest comet ever discovered.
BB, named after its discoverers, measures 62 miles (100 km) across – more than 100 times the diameter of a typical comet. Usually comets are no larger than about half a mile (1 km) in diameter.
It has been called the largest comet found in recorded history, although some have suggested that Comet Sarbat, which is over 513,000 miles wide and observed during the close approach of 1729, is larger.
It is also believed that the mass of BB is at least 1 million times greater than that of typical comets, as well as 100 times its diameter.
BB is more than 1.8 billion miles (2.9 billion km) away from Earth, but is slowly approaching the center of the Solar System.
It has been inside the orbit of Neptune since March 2014 and will pass inside the orbit of Uranus in December 2022.
In January 2031, it will make its closest approach to Earth – about 930 million miles from our planet. Fortunately it does not pose a threat to humanity.
Only one active comet has been observed from the Sun – C/2010 U3 (Boattini) – and it was much smaller than Comet BB.
The new study was carried out by University of Maryland (UM) researchers, who say BB is one of the most distant comets discovered with a coma.
The researchers did not actually determine the size in the new study, but cited the size given by Bernardinelli et al. in their discovery announcement earlier this year as being at least 100 km.
Study author Tony Farnham, a research scientist in the UMD Department of Astronomy, said: ‘These observations are pushing the distances for active comets up dramatically further than previously thought.
Often called ‘Dirty Snowballs’ or ‘Icy Dirtballs’, comets are clusters 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 heats up, and the ice begins to evaporate, forming a coma.
How far away from the Sun the ice begins to evaporate depends on what type of ice it is – either water, carbon dioxide, carbon monoxide, or some other frozen compound.
Scientists first discovered Comet Bibi in June 2021 using data from the Dark Energy Survey, an international effort to survey the sky over the Southern Hemisphere.
Images of Comet Bernardinelli-Bernsteinomet from 2018 and 2020, showing coma with ‘sunward side asymmetry’
The survey captured the bright nucleus of the comet but did not have high-enough resolution to reveal the envelope of dust and vapor that formed when the comet was active.
When Farnham heard of the discovery, he immediately wondered whether images of BB had been captured by NASA’s Transient Exoplanet Survey Satellite (TESS), which observes an area of the sky for 28 days at a time.
Believing that TESS’s longer exposure time could provide more detail, Farnham and his colleagues combined thousands of images of Comet BB collected by TESS from 2018 to 2020.
By stacking the images, Farnham was able to increase the contrast and get a clearer view of the comet. Because the comets move, they had to layer the images so that Comet Bb would align properly in each frame.
Researchers studied images from the Transient Exoplanet Survey Satellite, a NASA mission spent two years searching for transiting exoplanets (artist’s impression).
That technique removed errant specks from individual shots while magnifying the comet’s image, allowing researchers to see a faint glow of dust surrounding Bb – evidence that Bb had a coma and was active.
To make sure the coma wasn’t just a blur caused by the heap of images, the team repeated this technique with images of inactive objects from the Kuiper Belt, a doughnut-shaped ring of icy objects that extend beyond the orbit of Neptune. is spread.
When those objects appeared crisp, without any haze, the researchers were led to believe that the faint glow around Comet BB was actually an active coma.
The size of Comet BB and its distance from the Sun suggest that the vaporized ice that forms the coma is dominated by carbon monoxide.
Since the evaporation of carbon monoxide can begin when it is five times further from the Sun than comet Bb, it is likely that Bb was active well before it was observed.
The Kuiper Belt, where icy debris from the early Solar System is abundant, is far away…