A newly discovered comet may appear bright as a star in the night sky in the fall of 2024.
The comet, known as C/2023 A3 (Tsuchinshan-ATLAS), was first noted by the Asteroid Terrestrial-impact Last Alert System (ATLAS) telescope project in South Africa on February 22, according to Minor Planet Center (opens in new tab). Astronomers at the Purple Mountain Observatory in China also discovered the comet independently on January 9, so both observatories are cited in the comet’s full name. Skywatchers around the world have since observed it in new and old images, with the earliest detection found in images taken by a wide-field camera on a telescope at the Palomar Observatory in California on December 12, 2022.
Currently, C/2023 A3 is between Saturn and Jupiter, according to EarthSky (opens in new tab). It is traveling at a lightning-fast 180,610 mph (290,664 km/h) and is likely to make its closest approach to Earth on October 13, 2024.
Astronomers estimate that the comet only orbits the sun once every 80,660 years. This time around, the comet will come closest to the sun — known as perihelion — on Sept. 28, 2024, according to EarthSky.
Of course, all of this depends on the comet staying in one piece. Comets are loosely bound balls of ice, rock and dust, and they often break apart as they approach the Sun and begin to heat up.
If the comet is coherent, according to EarthSky, it could become visible in amateur telescopes in June 2024 before it passes between Earth and the sun on its way to perihelion. At perihelion, the comet will be low on the eastern horizon and may not be visible to many viewers on Earth; as it swings past Earth on its outward journey into the solar system, it will appear higher in the sky. Skywatchers will likely get their best view in late October as the comet moves through Serpens Caput (the western part of the constellation Serpens) and into the constellation Ophiuchus in the evening sky.
Seen from Earth, the comet could be as bright as the brightest stars in the sky during its upcoming flyby, according to EarthSky. This is brighter than green comet C/2022 E3 that just passed Earth in January. That comet had a brightness of about magnitude +4.6, just visible to the naked eye. The new comet may have a magnitude of 0.7, potentially peaking at magnitude -5, looks like Venus at its brightest (opens in new tab). (Lower numbers mean greater brightness on the stellar magnitude scale.)
Much is still unknown about C/2023 A3, including its size. Without more data, astronomers are still debating the comet’s chances of survival. In a message chain for astronomers (opens in new tab)University of Pennsylvania postdoctoral researcher Qicheng Zhang (opens in new tab) summed up the situation, calling C/2023 A3 the most promising comet for naked-eye views in years, but warned that those hopes could be dashed. “C/2023 A3’s survival, although promising, is not guaranteed at this time,” Zhang wrote.