A comet closing in on the sun has seemingly regrown “horns” of vaporized ice after a new cryovolcanic operation was triggered deep inside the interstellar object. Another eruption was observed in July.
As the comet 12/Pons-Brooks gets ready for its close approach to the sun next April, it is undergoing some dramatic changes, including huge eruptions of vaporized ice and gas from deep inside its 18-mile-wide core.
The gas is being vented through cracks in 12P that have broken due to the pressure, and their irregular shape has caused the gas to vent in a strange and oblong way. Thus, 12P hasn’t developed a regular tail, but is shooting its gases out through two holes in one side, giving it the appearance of a pair of “horns.”
The most recent eruption, which began on October 5, has increased its brightness by about 40 times, according to media reports. The huge venting of gas has created a cloud some 373,000 miles across, which is reflecting a lot more sunlight than before.
The comet is still about 3AU (three times the distance of Earth’s orbit) from the sun, but it’s expected to make its closest pass in April 2024, at which time it’ll be about 1.55AU from the Earth. Comet 12P will be difficult to see with the naked eye, but should be easily visible in telescopes or binoculars, appearing about as bright as Jupiter’s moon Ganymede.
If you miss it, you’ll have to wait until 2095 to see Comet 12P again.