Comet ATLAS (C/2024 G3) is currently descending toward the Sun and is expected to reach perihelion at approximately 10:15 UTC on January 13.
C/2024 G3 is a long-period, sungrazing comet discovered on April 5, 2024, by the ATLAS survey in Chile using a 0.5-meter reflector telescope. Initially, it was thought to be a new comet from the Oort cloud with minimal chances of surviving perihelion due to its weak absolute magnitude (H=9). However, refined orbital data revealed it is likely a dynamically old comet that has previously approached the Sun.
By October 30, 2024, the comet had reached an apparent magnitude of 11.9 and was visible with large telescopes. By mid-December, it brightened to 8th magnitude, becoming visible in Scorpius during dawn for observers in southern and equatorial regions. By the end of December, its magnitude increased to 5 – 5.5, with a coma spanning about two arcminutes and a tail up to 18 arcminutes long.
On January 2, 2025, an outburst was reported by astronomer Terry Lovejoy, with the comet’s magnitude surging to 3.7 photographically and 3.2 visually. By January 3, the comet had brightened further to a magnitude of 2 – 2.4, making it visible to the naked eye.
The comet entered the ESA/NASA LASCO C3 field of view at around 06:00 UTC on January 11.
It was observed from the International Space Station, with Astronaut Don Pettit capturing striking photographs at approximately 09:00 UTC on Thursday, January 9. “It is very bright now and starkly visible to the naked eye,” Pettit commented.
Juan Jose Ortiz observed the comet on Friday morning, January 10, from Metepec, Mexico. “The comet was surrounded by the orange glow of dawn just before sunrise on January 10,” Ortiz remarked.
As the comet nears the Sun, solar heating is expected to cause a significant increase in brightness. It is currently close to magnitude 0 and could brighten by another 100-fold over the weekend. If current trends continue, its magnitude may reach -5 (twice as bright as Venus) on January 13, when the comet passes just 0.09 AU from the Sun.
It might even be visible in the daytime sky,” said Nick James of the British Astronomical Association. “However, the sun will be only 5 degrees away. Observing with the sun so nearby is dangerous and should only be attempted with great care.”
References:
1 What’s up in space – Spaceweather.com – January 11, 2025
2 Comet C/2024 G3 (ATLAS) – COBS – Accessed on January 11, 2025
3 C/2024 G3 in outburst? – Jan 2.76, 2025 UT – CML – Accessed on January 11, 2025
4 C/2024 G3 (ATLAS) – JPL/SSD – Accessed on January 11, 2025