What Will Happen to “Sungrazer” Comet C/2024 S1 (ATLAS)?

Find Comet C/2024 S1 (ATLAS) on our Night Sky Map

Don’t miss Comet Tsuchinshan-ATLAS

Two Comets in the Same Month?

Just as anticipation was building for the arrival of Comet C/2023 A3 (Tsuchinshan-ATLAS), another comet suddenly appeared.

Comet C/2024 S1 (ATLAS) was discovered on September 27, 2024, by a system of robotic telescopes called the Asteroid Terrestrial-impact Last Alert System (ATLAS).

ATLAS has helped astronomers discover around 100 comets, including Tsuchinshan-ATLAS in 2023. This is why the comets have similar-looking names.

C/2024 S1 is a “sungrazer” comet. It will arrive at perihelion—its closest point to the Sun—on October 28, 2024. There were hopes it might become bright around this date. However, comets are notorious for being highly unpredictable, and the latest indications are discouraging.

What Is a Sungrazer?

C/2024 S1 belongs to a group of comets known as Kreutz sungrazers, which pass extremely close to the Sun.

How close is extremely close? It’s within around 1,500,000 kilometers (900,000 miles)—roughly the size of the Sun itself.

Two of the most spectacular comets in history, the Great September Comet of 1882 and Comet Ikeya–Seki in 1965, were Kreutz sungrazers. Both of these comets could be seen in the daytime sky.

An Uncertain Future

Nothing is certain when it comes to comets—and things can change quickly. Last Wednesday, October 9, a group of Italian astronomers suggested that C/2024 S1 might be disintegrating. But the situation remained unclear.

“I don’t think we have clear evidence that the comet is disintegrating,” Man-To Hui, an astronomer at the Macau University of Science and Technology, told timeanddate.com on Friday, October 11.

“Definitely more data will be needed before we can be certain about what’s going on with the comet.”

As more data came in over the weekend, it appeared that C/2024 S1 is fading slightly—even through it is getting closer to the Sun.

“I have to say that the fate of the comet seems more pessimistic,” Professor Hui told us on Sunday, October 13.

“If the hiatus lasts overlong, or the comet starts to fade noticeably, it is more likely that the comet is disintegrating—and the hope for a spectacular heavenly show may well be over.”

Eyes on the Sky

One of the groups that has been gathering data on C/2024 S1 in recent weeks is the Comet Chasers project, which connects schoolchildren with research-grade telescopes around the world.

“We noted that a new comet had been discovered and immediately started to make observations,” said Helen Usher, the leader of the project. “Observations made soon after discovery help scientists to confirm if it is a comet and calculate its orbit.”

The Comet Chasers collaboration has so far included observations from Spain, the UK, Croatia, Greece, and Mozambique.

“We’re really grateful to the Faulkes Telescope and Global Sky Partners projects for facilitating our telescope access, and the support from amateur astronomers at the British Astronomical Association’s Comet Section,” said Helen, who is a PhD student studying comets at the Open University in the UK.

Will We See C/2024 S1?

If C/2024 S1 becomes bright, it will only be for a short time around October 28—the date of perihelion, when it is closest to the Sun.

WARNING: Do NOT look at objects close to the Sun, and NEVER point binoculars or a telescope in the direction of the Sun. This can cause immediate and permanent eye damage.

Either side of October 28, C/2024 S1 will rise above the eastern horizon shortly before the Sun.

The position of the comet before sunrise will be slightly more favorable to observers in the Southern Hemisphere, particularly in the days leading up to October 28.

Find Comet C/2024 S1 (ATLAS) on our Night Sky Map

Whatever happens to Comet C/2024 S1 between now and the end of October, a thin Waning Crescent Moon will hang low in the eastern sky—close to the comet’s position—on the mornings of October 30 and 31.