Washington, Jan 20: NASA’s solar observatory caught for the very first time on camera a comet’s fiery end as it flew too close to the sun’s blazing surface.
The comet’s disintegration on July 6, 2011 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 Centre in Greenbelt, who is the project scientist for NASA’s Solar Dynamic Observatory (SDO), which snapped images of the comet. “We’ve been telling people we’d never see one in SDO data.”
But an ultra bright 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 journal Science reports.
The movie is more than just a novelty. As detailed in a paper, 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 to 300 feet long and has about as much mass as an aircraft carrier, according to a NASA statement.
“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, California., study co-author and 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,” added Schrijver.
Typically, comet-watchers see the Kreutz-group comets only through images taken by coronagraphs, a specialized telescope that views the Sun’s fainter out atmosphere, or corona, by blocking the direct blinding sunlight with a solid occulting disk.
Such “sun-grazer” comets obviously destruct when they get close to the sun, but the event had never been witnessed.