Like a moth getting a tad too close to a campfire, a comet has been spotted taking a deep death-dive into the sun.
Although "sun-grazing" comets are well known, the twin STEREO (Solar TErrestrial RElations Observatory) satellites and SOHO (Solar and Heliospheric Observatory) watched a comet take the plunge and scientists from the University of California, Berkeley predicted the time and location where the comet would impact.
What's more, the researchers suspect this comet was made of strong stuff; it would appear that some portion of the cometary nucleus fell as deep as the sun's chromosphere.
If the comet was playing "chicken" with our star, it might not have won, but it was certainly determined to last the distance!
ANALYSIS: What is a sun-grazing comet? It's a group of comets that like to live dangerously.
Usually, we lose sight of sun-grazing comets when they get too close to the sun as the brightness of the sun overwhelms the reflected light from the comet. But using the SOHO/STEREO data, solar astronomers were able to track the trajectory of the comet to a very high precision deep into the sun's corona.
"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, a post-doctoral fellow at UCB.
Raftery's team were interested in this particular comet -- thought to be part of the Kreutz family of comets -- as its detection in March suggested it was on a collision course with the sun. Using the two 'eyes' of STEREO, the team were able to track the incoming comet accurately to a point where they were able to make a prediction two days before impact: the comet would "hit" the sun within an area measuring only 1,000 miles across.
This is a solar first.
But it gets better.
As the researchers had a good idea as to where the comet plummeted, they scoured the online database of the Hawaiian Mauna Loa Solar Observatory to see if there was any trace of the comet within that impact zone.
Sure enough, pulling up observations of the limb (edge) of the sun, there was a very short track, lasting for 6 minutes, only a few thousand miles from the sun's surface. This means that this particular comet survived the dive through the sun's multi-million degree atmosphere, finally getting exterminated by the 180,000 degree Fahrenheit chromosphere -- the layer of the sun that separates the solar "surface" (the photosphere) from the sun's atmosphere (the corona).
It is thought that although comets are composed of ice, dust and rock, this comet contained heavier elements that didn't evaporate as readily as many sun-grazing comets. Its short tail -- the vapor released from the cometary nucleus when it's heated -- appears to agree that this comet was made of strong stuff.
Although this study is fascinating, studying comets isn't the main focus of the UCB team, they're usually working on the physics behind coronal mass ejections.
"It was supposed to be an exercise, but it took over our lives," Raftery said.
Perhaps a career in "comet death forecasting" is on the cards...
Watch the twin STEREO footage of the comets death dive:
Comet movie from Science News on Vimeo.
Source: Berkeley press release
Tags: Comets, Solar System, Space Telescopes, Space Weather, The Sun
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