Comet Takes Death-Dive Into the Sun
Written by Nancy Atkinson
Was this comet infested with the neural parasites that caused mass insanity on the planet Deneva in the original Star Trek TV series (Operation Annihilate)? Probably not, but this is a very cool video. Solar physicists at the University of California, Berkeley, have captured for the first time the collision of a comet with the sun. "We believe this is the first time a comet has been tracked in 3-D space this low down in the solar corona," said Claire Raftery who worked with colleagues Juan Carlos Martinez-Oliveros, Samuel Krucker and Pascal Saint-Hilaire.
Using instruments aboard NASA's twin STEREO spacecraft, the team tracked the comet as it approached the sun and estimated an approximate time and place of impact, a zone within a circle about 1,000 kilometers in diameter. The data they had were good enough to chart the comet's approach for two days before impact.
Martinez-Oliveros' attention was first drawn to the comet after seeing it mentioned in a summary of March 12, 2010, observations by STEREO and by SOHO, the Solar and Heliospheric Observatory. The comet's long, bright tail of dust and ions tagged it as a sungrazing comet seen often by solar astronomers and observatories such as STEREO.
Sungrazing comets, comprised of dust, rock and ice, are seldom tracked close to the sun because their brightness is overwhelmed by the solar disk. This comet apparently survived the heat of the corona and disappeared in the chromosphere, evaporating in the 100,000-degree (Kelvin) heat.
The physicists concluded that the comet was probably one of the Kreutz family of comets, a swarm of Trojan or Greek comets ejected from their orbit in 2004 by Jupiter, and that it made its first and only loop around the sun. The swarm probably resulted from the disintegration of a larger comet.
Based on the comet's relatively short tail, about 3 million kilometers in length, the researchers believe that the comet contained heavier elements that do not evaporate readily. This would also explain how it penetrated so deeply into the chromosphere, surviving the strong solar wind as well as the extreme temperatures, before evaporating.
All members of the team study explosive events on the sun, such as coronal mass ejections, and the hot ionized plasmas that they throw into space. The researchers' detour into cometary physics was purely accidental, they said.
"It was supposed to be an exercise, but it took over our lives," Raftery said.
The team presented their findings at the 216th American Astronomical Society Meeting this week in Miami, Florida.
Source: UC- Berkeley
Powered by WizardRSS | Full Text RSS Feeds
