2024-07-22 11:48:05
Comet C/2023 A3 September 27 should reach the closest point to the Sun (perihelion), and on October 13 it may be the closest to Earth (more than 71 million km away). If the comet comes this close to Earth, it will be as bright as most stars in the night sky, making it possible for people to observe it with the naked eye for weeks.
But in a new study, July 8 uploaded to arXiv Advance Publications Sitestudy author Zdenek Sekanina — an astronomer at NASA’s Jet Propulsion Laboratory who has studied comets for more than 50 years — says Comet C/2023 A3 may meet its end before reaching perihelion.
Large comets usually break up when they reach perihelion, as the Sun’s massive gravity pulls on the icy objects. This is exactly what happened to comet ISON, which, according to the European Space Agency, in 2014. when it came close to the Sun, it was severely disrupted.
Scientists previously hypothesized that this would also happen to two other comets that have recently passed Earth: Comet Nishimura, which passed close to the Sun last September, and Comet 12P/Pons Brooks, also known as the “Devil’s Comet,” which survived a trip near the Sun these April of the year.
But comets like C/2023 A3 can also break up as they approach the Sun, as increased radiation from the Sun compresses preexisting cracks. So did comet C/2019 Y4, which spectacularly broke up into dozens of pieces before reaching perihelion in 2020, according to NASA.
In the new paper, Sekanina says that several facts indicate that comet C/2023 A3 will “inevitably disintegrate”.
First, the comet didn’t get as bright as most other comets on its approach to the Sun, meaning its nucleus — or outer layer — could be damaged. Second, the comet’s dust tail is much thinner than it should be and is “peculiarly oriented,” which also indicates that the comet is not solid. Third, the comet appears to be undergoing “non-gravitational acceleration,” likely due to internal gas flows that cause the nucleus to break apart.
However, not everyone agrees with Z. Sekanina’s observations.
“It doesn’t look like a comet breaking up to me,” says Nick James, an astronomer at the British Astronomical Association who was not involved in the study. – Use [žodį] “inevitable” in any prediction about a comet may be unwise.”
But James noted that the new paper is “another good reason to watch this comet every chance you get.”
Parengta pagal „Live Science“.
2024-07-22 11:48:05