C/2024 G3 (ATLAS) is a long-period (160000 year), sungrazing comet, which will reach perihelion on 13 January 2025, at a distance of 0.09 AU from the Sun.

It could become the brightest comet of 2025, possibly exceeding apparent magnitude of −3.5. The comet is visible in the southern hemisphere before and after perihelion. It can only be observed in the daytime sky around perihelion in the northern hemisphere.

Links:
Once-in-a-160000-year comet G3 ATLAS could shine as bright as Venus next week. Here’s what to expect

A bright ‘Sun-skirting’ comet will grace southern skies this week. Here’s how to see it

C/2024 G3 (JPL Small-Body Database)