Kreutz comet vaporized as it flew too close to the Sun

For the first time, a death-diving comet, from a group known as the Kreutz comets, has been observed as it vaporized as it flew too close to the Sun.

Kreutz comets (more than a thousand known) are a family of icy bodies, that pass very near to the sun’s surface on their orbits through the solar system.

On July 6, 2011, a comet was caught doing something never seen before: dying a scorching death as it flew too close to the Sun. That the comet met its fate this way was no surprise — but the chance to watch it first-hand amazed even the most seasoned comet-watchers.

“Comets are usually too dim to be seen in the glare of the Sun’s light,” says Dean Pesnell at NASA’s Goddard Space Flight Center in Greenbelt, Md., who is the project scientist for NASA’s Solar Dynamics Observatory (SDO), which snapped images of the comet. “We’ve been telling people we’d never see one in SDO data.”

But an ultrabright comet, from a group known as the Kreutz comets, overturned all preconceived notions. The comet can clearly be viewed moving in over the right side of the Sun, disappearing 20 minutes later as it evaporates in the searing heat. The movie is more than just a novelty. As detailed in a paper in Science magazine appearing January 20, 2012, watching the comet’s death provides a new way to estimate the comet’s size and mass. The comet turns out to be somewhere between 150 and 300 feet long and to have about as much mass as an aircraft carrier.

“Of course, it’s doing something very different than what aircraft carriers do,” says Karel Schrijver, a solar scientist at Lockheed Martin in Palo Alto, Calif., who is the first author on the Science paper and is the principal investigator of the Atmospheric Imaging Assembly instrument on SDO, which recorded the movie. “It was moving along at almost 400 miles per second through the intense heat of the Sun — and was literally being evaporated away.”

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