Devil Comet Loses Horns: Unusual Green Hue and Mysterious Shadow Emerge After Violent Outburst

The massive cryovolcanic comet, dubbed the Devil Comet due to its devil-like horns, recently underwent another explosive event on its journey toward Earth. Unlike previous outbursts, astronomers did not observe a dark lane in its coma.

The Devil May Have Gone for Good

The colossal "devil comet," hurtling towards the sun, may have shed its infamous horns following its recent and most violent eruption. Comet 12P/Pons-Brooks, an immense 10.5-mile-wide cryovolcanic comet, is set to make its closest approach to Earth in over 70 years next summer.

Composed of an icy nucleus filled with ice and gas, the comet's cryomagma, or superheated frosty innards, erupt when exposed to the Sun's radiation, creating a reflective coma of dust and cryomagma that brightens its appearance.

Having undergone three major eruptions on July 20, October 5, and Halloween, each event caused the comet's coma to expand into an irregular shape resembling horns.

The latest eruption on November 14 was the most extreme, making the comet over 100 times brighter. However, this time, its iconic horns were conspicuously absent, with the coma appearing perfectly circular, according to Nick James of the British Astronomical Association.

The origin of the horns lies in an irregularity within 12P's nucleus, as described by BAA astronomer Richard Miles. A notch on the nucleus obstructs the outflowing gas during eruptions, creating horn-like features. The recent disappearance of the horns remains unexplained, though speculation suggests the frequent eruptions may have damaged the blocking notch.

Amateur astronomer Eliot Herman, documenting the comet's activity since its first eruption, expressed surprise at the coma's expansion without horns and uncertainty about their future reappearance. Herman remarked, "The devil may be gone [for good]."

Horns Replaced by Green Hue and Rare Shadow

Speeding at about 40,000 mph (64,300 km/h) on its final stretch of a 71-year orbit around the Sun, Comet 12P is swiftly approaching its perihelion, set to occur on April 24, 2024. This event will mark its closest point to the sun before being flung around the star and into the outer reaches of the Solar System, where it will remain for the majority of its orbit.

The comet is not expected to revisit the inner solar system until the year 2094. A noteworthy moment will be on June 2, 2025, when it is hoped that Comet 12P will be visible to the naked eye during its closest approach to Earth.

Recent images captured by Herman have uncovered intriguing features of Comet 12P. Alongside its customary eruptions, a surprising green hue has manifested in the comet's coma. This unique coloration is linked to the presence of dicarbon, a substance that emits green light when interacting with sunlight.

In addition to the green hue, Herman's observations detected an unusual dark patch in the comet's vivid coma, resembling a curved gap. Unlike the dark lane responsible for the comet's distinctive horns, experts suggest that this particular shape is a shadow cast by the outflowing cryomagma, as detailed by Spaceweather.com.

The journey toward Earth for Comet 12P holds the promise of continued eruptions, possibly escalating in intensity. Following its closest approach, the comet will succumb to gravitational forces, propelling it back to the outer Solar System.

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