A massive volcanic eruption on ‘Devil Comet’, as it races towards Earth and might make its closest approach next year, is likely to have removed its distinctive ‘horns’ that earned it the sinister nickname.
After the latest and most violent outburst last week, the comet’s trademark head spikes were not seen as they did after earlier eruptions. However, astronomers noticed many new characteristics in the Devil Comet, which included a mysterious “shadow” and a rare green hue.
The massive 10.5-mile-wide (17-kilometre) ‘Devil Comet’, scientific name 12P/Pons-Brooks (12P), has been hurtling towards Earth and will make its closest approach of more than 70 years next summer.
Comet 12P is cryovolcanic, meaning it has an icy shell, or nucleus filled with gas and ice. After the comet absorbs enough radiation from the sun, its cryomagma or frosty innards get superheated. The pressure increases inside the nucleus till the shell cracks and the icy guts of the comet spray into space.
After every eruption, the comet’s dust and a fuzzy, reflective cloud of cryomagma expand and make it appear brighter to astronomers. Till now, the comet had three major eruptions. One took place on July 20 when it was seen exploding for the first time in 69 years and the other explosion happened on October 5 when the eruption was more vigorous; and the third on Halloween (October 31) which was a comparatively less intense outburst.
Why do horns appear on the comet and will they appear in future?
Every time an explosion occurred on the comet, its coma took an irregular shape with a “dark lane” which made it appear to have grown a pair of horns. On November 14, the comet had another major eruption, which was the most extreme outburst till now.
Astronomers watched as the comet became more than 100 times brighter than normal for some days after its coma expanded, reported Spaceweather.com. However, this time they could not see its distinctive horns.
“The coma seems perfectly circular this time,” said Nick James, director of the British Astronomical Association’s (BAA) comet section, while speaking to Spaceweather.com.
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Speaking to Live Science, BAA astronomer Richard Miles said that the comet’s horns appeared because of an irregularity in the shape of 12P’s nucleus. The outflowing gas will be partially obstructed by a notch which is sticking out on the nucleus, he added.
Amateur astronomer and photographer Eliot Herman, who has been capturing the comet since the first eruption took place, was surprised to see the coma expanding without the appearance of horns.
He told Live Science he is unsure if another appearance will be made by them in the future.
“The devil may be gone [for good],” he said.
(With inputs from agencies)
Dr. Thomas Hughes is a UK-based scientist and science communicator who makes complex topics accessible to readers. His articles explore breakthroughs in various scientific disciplines, from space exploration to cutting-edge research.
