Don’t miss your chance to see the cryovolcanic ‘devil comet’

Skygazers have the chance to view more than just a bright planet Mercury or April’s total solar eclipse over the next few days. An unusual “devil comet” or Comet 12P/Pons-Brooks will be visible across the night sky over the next several days and may make an appearance during the big eclipse on April 8th. Since it only makes one orbit around the sun every 71 years, seeing Pons-Brooks is generally a once-in-a-lifetime opportunity.

What is the ‘devil comet’?

Pons-Brooks is a 10.5 mile-wide ball of ice and rock. It has a stretched out or highly elliptical orbit and is currently heading in the direction of our sun. It has a core made up of solid ice, gas, and dust that is surrounded by a frozen shell or nucleus. This nucleus is also covered by a cloud of icy dust called a coma that slowly leaks out of the center of the comet.

Comet 12P/Pons-Brooks’ swirling coma. This image is a composite of three very specific colors, showing the comet’s ever-changing ion tail in light blue, its outer coma in green, and highlights some red-glowing gas around the coma in a spiral. The spiral is thought to be caused by gas being expelled by the slowly rotating nucleus of the giant iceberg comet. CREDIT: Copyright Jan Erik Vallestad

Unlike most other comets, Pons-Brooks is cryovolcanic. It frequently erupts when solar radiation opens up fissures in the nucleus. This causes highly pressurized icy cryomagma to spew into space. When this occurs, the cloud of icy dust that surrounds it expands and appears brighter than usual.

Pons-Brooks had a major eruption for the first time in 69 years in July 2023, which left it with two distinct trails of gas and ice that resemble a pair of devil horns. It has continued to erupt fairly frequently.

[Related: ‘Oumuamua isn’t an alien probe, but it might be the freakiest comet we’ve ever seen.]

When will it be visible?

Throughout the next few weeks, Pons-Brooks may be visible to the naked eye as it travels through the inner solar system. It will remain so until April 2, as it travels closer to the sun and won’t be visible in the dark night sky. It will be closest to Earth on June 2, when it is headed away from the sun. It does not pose any known threats to Earth and will be about 139.4 million miles away.

SETI institute postdoctoral fellow Ariel Graykowski told Gizmodo that it is set to become even more active in the coming weeks and will be visible to the naked eye with a maximum brightness magnitude around 4.0. The lower the magnitude, the brighter the appearance.

“The limit for naked eye objects in dark, moonless skies is around 6 magnitudes,” Graykowski said, so “it won’t be super obvious in the sky.”

Where should I look?

In the Northern Hemisphere, it is most visible in the early evening towards the west-northwest horizon. Pons-Brooks is near the Pisces constellation and sits low in the northwestern sky. It should appear like a glowing ball of ice, with its forked horns following behind it.

[Related: Halley’s comet is on its way back towards Earth.]

“The comet will brighten a bit as it gets closer to the sun, and it should be visible to the naked eye low in the west about an hour after sunset,” Paul Chodas and Davide Farnocchia from NASA’s Jet Propulsion Laboratory told CNN. “You should go to a location away from city lights and with an unobstructed view of the western horizon. It would be advisable to use a pair of binoculars, since the comet may be hard to locate without them.”

Will it appear during the April 8 solar eclipse?

Maybe. The forecast remains uncertain, but Pons-brooks could be visible if it flares significantly. It would only be seen by viewers in the path of totality–the area stretching from Texas northeast towards Maine where the moon will fully block the sun’s light.

According to EarthSky, “when the sky darkens, you’ll see the brightest planet Venus pop into view on one side of the sun. On the other side of the sun, you’ll find the second-brightest planet, Jupiter. And if Comet Pons-Brooks is bright enough, you’ll see it between Jupiter and the sun, but closer to Jupiter.”

It will not make an appearance again until 2097, so now is your chance to get a look.