A newly discovered comet could appear as bright as a star in the night sky in the fall of 2024.
The comet, known as C/2023 A3 (Tsuchinshan-ATLAS), was first observed on February 22 by the ATLAS (Asteroid Terrestrial-Impact Last Alert System) telescope project in South Africa Minor Planet Center (opens in new tab). Astronomers at the Purple Mountain Observatory in China also spotted the comet independently on Jan. 9, so both observatories are cited by the comet’s full name. Skywatchers around the world have since observed it in images new and old, with the earliest discovery being 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 said to be between Saturn and Jupiter earth sky (opens in new tab). It’s moving at a brisk 290,664 km/h (180,610 mph) and is expected to make its closest approach to Earth on October 13, 2024.
Astronomers estimate that the comet orbits the sun only once every 80,660 years. In that round trip, the comet will make its closest approach to the Sun — known as perihelion — on September 28, 2024, according to EarthSky.
All of this, of course, depends on the comet staying in one piece. Comets are loosely bound balls of ice, rock, and dust, and they often break up as they approach the Sun and begin to heat up.
If the comet stays together, it could become visible in amateur telescopes in June 2024, before passing between Earth and the Sun on its way to perihelion, according to EarthSky. At perihelion, the comet is low on the eastern horizon and may not be visible to many viewers on Earth; As it swings past Earth on its journey into the solar system, it will appear higher in the sky. Skywatchers will likely have their best views in late October, when the comet moves through Serpens Caput (the western part of the Serpens constellation) and into the Ophiuchus constellation in the evening sky.
Seen from Earth, the comet could be as luminous as the brightest stars in the sky during its upcoming flyby, according to EarthSky. This one is lighter than that Green Comet C/2022 E3 which just passed Earth in January. This comet was about +4.6 magnitude, just visible to the naked eye. The new comet may have a brightness of 0.7 mag and possibly peak at -5 mag. similar to Venus in its brightest form (opens in new tab). (Smaller 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 one News chain for astronomers (opens in new tab)Postdoctoral fellow at the University of Pennsylvania Qicheng Zhang (opens in new tab) summarized the situation, calling C/2023 A3 the most promising comet in years to allow naked-eye imaging, but warned that those hopes could be dashed. “The survival of C/2023 A3, while promising, is not guaranteed at this time,” Zhang wrote.