Comet survives close brush with Sun

Comet survives close brush with Sun


Astronomers looked on astonished today as an icy comet survived a close brush with the Sun. The celestial wanderer, called Comet Lovejoy after its discoverer, skimmed just 140,000 km (87,000 miles) above the Sun’s surface – around a third of the distance of the Moon from the Earth. 

Comet Lovejoy caught by SOHO’s Lasco 3 camera (NASA)

Experts reckoned it would be completely vaporised by the encounter. But remarkable images from Sun-watching satellites showed that it came through remarkably unscathed.

Also remarkable was that the comet’s tail, many millions of kilometres long, had become detached and was still visible as a ghostly feature to the left of the Sun in pictures from the SOHO satellite’s LASCO C3 camera, while the comet, to the right, appeared to be growing a new tail as it sped back out into space.

Comet tails point away from the Sun, due to pressure from the solar wind, so a retreating comet will eventually be travelling tail-first! (The horizontal streak through the comet’s head is an artefact introduced by the camera due to the brightness of its head). The comet was the brightest of a type termed a sungrazer that SOHO had ever pictured. It was discovered by Australian amateur astronomer Terry Lovejoy through his telescope in Brisbane.

Astronomers believe Comet Lovejoy is just a fragment of a vast supercomet that broke up in the 12th century. The resulting debris, now orbiting in the solar system as smaller comets, is known as the Kreutz family. 

Some Kreutz comets, such as Ikeya-Seki in 1965, do become so bright they can be seen with the naked eye in the daytime, though this is extremely rare.

Many much smaller Kreutz fragments, too small to be seen, graze past the Sun every day and disintegrate. Indeed, the latest NASA movie of Lovejoy heading towards the Sun showed a faint companion travelling in a parallel path alongside it.

You can see some fantastic movies of the comet’s close encounter with the Sun on the Sungrazing Comets website. And view the latest SOHO images of the Sun here.


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