Maybe it'll break up as it passes the sun. Maybe it will completely defy optimistic predictions. Maybe it will match the brightest comets seen in a century. It could all be Comet Tsuchinshan-ATLAS.
In January 2023, the previously unknown hairless star was caught in the field of view of the detectors at the Purple Mountain Observatory in Nanjing, China (Tsuchinshan is a transcription of the name), and in February, the South African Asteroid Terrestrial-impact Last Alert System (ATLAS) robotic telescope. Hence its somewhat cryptic name C/2023 A3 (Tsuchinshan-ATLAS).
On 27 September 2024, the comet's nucleus will pass closer to the Sun than the planet Mercury, but at that point, according to some predictions, it may break up and completely dissolve due to the tidal effects of our star. If that doesn't happen, two weeks later (12 October 2024) the cometary nucleus will be 71 million kilometres closer to Earth than the Moon is to the Earth - roughly 200 times farther. It will then travel in a very elongated orbit towards the periphery of the Solar System - it is predicted that in 2237 it will be at a distance two hundred times greater than the distance our planet orbits the Sun.
If all the optimistic forecasts come true, a bright spot with a hint of a tail will begin to appear over the southwestern horizon about an hour after sunset after October 12. Even though it will be disturbed by the Moon, be sure to watch it from places with good visibility and away from street lights. It will gradually pass through the Serpent's Head, the Serpent's Tail and the Serpent's Tail.
Perhaps the best will be after October 19, 2024, when the Moon moves into the second half of the night. A comet tail with an angular length of up to 20 degrees may be visible in the evening sky at that time!
But will Tsuchinshan-ATLAS really become a "great comet"? Similar to Hyakutake in 1996, Hale-Bopp in 1997, McNaught in 2007 or Neowise in 2020? "It's hard to say. All of these options are possible. Comets are like 'sky cats'. They have a tail and, like the terrestrial ones, they do what they see fit. But there's no other way to find out than by observation." They closed Jiří Dušek from Brno Observatory and Planetarium and Miloš Tichý from the Klet Observatory.
Institute of Astronomy of the CAS/ gnews - RoZ_07
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