Will Comet G3 ATLAS be active at perihelion?

The most anticipated comet of 2025 is just around the corner. Currently, the only comet that has the potential to become visible to the naked eye in 2025 is Comet C/2024 G3 ATLAS. The comet will reach perihelion on January 13th at 0.094 astronomical units (AU, 8.7 million miles or 14 million kilometers, inside Mercury’s orbit) from the Sun and could be as bright as -1 magnitude or higher .

Late December’s magnitude +4 comet G3 Atlas could be a great object low in the dawn sky for observers in the southern hemisphere… if (a big “what if”) it comes together and works as expected If you do.

In fact, the comet exploded during the first weekend of 2025, jumping from magnitude +4 to +1 (a 16-fold increase in brightness in a few days). This can be a sign of good (or bad) things to come in the near future.

“The comet has exploded in the last few days,” Nicolas Leforde told Universe Today. “If the explosion is associated with a collapse, we probably won’t see anything after perihelion. If the explosion is associated with a new active region or the fission of a large nucleus, then the simulation You could get a much better view.”

A recent message from the International Astronomical Union’s Central Astronomical Telegraph Office suggests an optimistic peak of magnitude -3 near perihelion after the explosion, if the comet stays together.

discovery

This comet was discovered on the night of April 5, 2024, as a +19 magnitude celestial object located in the constellation Taurus in the southern hemisphere, by the Asteroid Earth Collision Last Alert System (ATLAS).

The orbital period of this object is approximately 160,000 years. It’s unclear whether Comet G3 Atlas is the first visitor to the inner Solar System or a new resident from the distant Oort Cloud. The last time a comet rocked through the inner solar system (assuming it had done so in the past as well), wearing clothes was the new thing among our Homo sapiens ancestors.

Comet G3 at perihelion: perish or prosper?

It will be difficult to see whether this comet will be visible. Unlike last year’s comet C/2023, A3 Tuchinshan-ATLAS, which spread its spectacular tail during its evening appearance, G3 ATLAS will leave our solar neighborhood hugging the southern horizon in the twilight sky. It will be timid around perihelion.

If G3 ATLAS overperforms at perihelion, a daytime comet could be just around the corner…but it will be a difficult viewing since it will be so close to the Sun. If you are trying to spot a comet during the day, be sure to be behind a building or structure that completely blocks the sun’s dangerous glare from your view. Similar to A3 T-ATLAS, the NASA/ESA SOHO joint observatory will observe comets passing near perihelion through the LASCO C3 viewer.

Recommended products for Comet G3 ATLAS

At perihelion on Monday, January 13, 2025, the comet will be visible at just 4 degrees from the Sun. The comet will also make its closest approach to Earth on the same day at a distance of 0.938 AU. If it holds together well at perihelion, the comet could reach magnitude -4 (about as bright as Venus) around the same time.

This is an image of the comet taken by Nick James with a remote telescope in late December.

Comet G3 ATLAS has been elusive so far. The comet is shy, grazing just 5 degrees above the horizon at dawn until perihelion in early January for Northern Hemisphere observers. The comet reappears low in the western sky after dusk, but because the comet is running south parallel to the horizon, people living in the north will see it briefly hovering 5 to 10 degrees above the horizon at dusk. I can only see it. As is usually the case with comets, it is better visible in the southern hemisphere.

Here’s a breakdown of what to expect from this comet in the coming months. (Note that “passing close” indicates a bond of 1 degree or less):

January

6 – Near the Lagoon Nebula (Messier 8) 7 – Near the Globular Cluster (Messier 28) 8 – Across the ecliptic plane to the north 11 – Enter SOHO LASCO C3 view 13 – At perihelion, less than 5 degrees from the Sun 14 – From the Sun Capricornus exit 15 SOHO LASCO C3 view across, and south across the ecliptic plane 21 – Cutting the Corner of Microscope 22 – Crossing Pisces Austrinus

February

1 – May fall below 6th magnitude 6 – Intersects the constellation Gurus 21 – Carves the corner of the constellation Sculptor 25 – Intersects the constellation Phoenix

march

March 1st: There is a possibility that it will fall below +10 mag.

Observing and imaging this comet will be difficult due to two main factors. First, for Northern Hemisphere observers, comets never actually leave the low-contrast twilight sky. Second, the comet’s magnitude quoted is “filled in” over its entire apparent surface area, reducing the comet’s apparent brightness by a notch or two.

In this regard, we can expect Comet G3 ATLAS to exhibit excellent performance. My strategy is to find an observational high ground and the lowest, flattest horizon I can find (for example, the ocean visible from a beach) and sweep the horizon with binoculars at low magnification to watch for comet fluff.

We wish you good luck and clear skies as you search for the first comet of 2025.