Incoming a comet that may be visible to the naked eye as it passes Earth later this year may be doomed to disintegrate before we get a chance to see it up close, a new study suggests. Recent observations indicate that the comet has already begun to fragment and may disintegrate completely in the next few weeks or months. However, some experts disagree.
Astronomers at China’s Purple Mountain Observatory first spotted comet C/2023 A3, also known as Tsuchinshan-ATLAS, on January 9, 2023, and it was confirmed on February 22 of that year, when NASA’s Earth Asteroid Final Warning System ( ATLAS) noticed it revolving towards the sun. The trajectory of the comet suggests that this may be the first close approach the sun and that it may eventually be thrown out of solar system.
C/2023 A3 is due to reach its closest point to the sun, or perihelion, on September 27 and may make its closest approach to Earth on October 13, when it will be about 44 million miles (71 million kilometers) from our planet . If the comet wanders this close to Earth, it will be as bright as most stars in the night sky, making it it is possible for people to notice it with the naked eye for several weeks.
But in a new study uploaded July 8 to the preprint server arXivauthor of the study Zdenek Sekanina — an astronomer at NASA’s Jet Propulsion Laboratory who has studied comets for more than 50 years — argues that C/2023 A3 may meet its end before reaching perihelion.
“The comet has entered an advanced phase of fragmentation, in which an increasing number of dry, broken refractory solids remain collected in dark, porous patches of exotic shape,” Sekanina wrote in the paper. These fragments will eventually become “undetectable as they gradually dissipate into space,” he added.
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Large comets usually fragment at perihelion as the sun’s immense gravity pulls on the icy objects. That’s what happened to comet ISON, which was violently torn apart during a solar flyby in 2014, according to European Space Agency.
Scientists previously assumed this would also happen to two other comets that recently passed by Earth: Comet Nishimura, which with a sling around the sun in September last year; and Comet 12P/Ponce Brooks, also known as the “Devil’s Comet,” which survived its trip around the sun in April this year.
However, comets like C/2023 A3 can also fragment as they approach the sun, as the increase in solar radiation puts pressure on previous fractures. That’s what happened to comet C/2019 Y4, which spectacularly disintegrated into dozens of pieces before its close approach in 2020, according to NASA.
In the new paper, Sekanina argues that several lines of evidence point to the “inevitable collapse” of C/2023 A3.
First, the comet failed to brighten as it approached the sun, as most other comets do, meaning that its nucleus or envelope may not be completely intact. Second, the comet’s dust tail is much thinner than it should be and has a “peculiar orientation,” which also suggests that the comet is not whole. Third, the comet appears to be experiencing “non-gravitational acceleration,” most likely caused by internal gas jets pushing on the nucleus.
However, not everyone agrees with Sekanina’s observations.
“That doesn’t look like a comet breaking up to me.” Nick Jamesan astronomer with the British Astronomical Association, who was not involved in the research, said Spaceweather.com. “To use [the word] “inevitable” in any comet prediction may be unreasonable,” he added.
However, James noted that the new paper is “another good reason to observe this comet whenever we can.”
