ESA's Rosetta orbiter captures rare outburst of gas from Comet 67P

Okay, everybody stop snickering, even heavenly bodies suffer from occasional stomach discomfort due to bloating and gas.  Comet 67P/Churyumov–Gerasimenko will finally reach perihelion today, Thursday, Aug. 13, the closest point to the sun during its 6.5-year orbit of our solar system.  As the dog-bone-shaped comet cruises closer to the sun, its internal structure begins to rumble due to solar wind and radiation, causing ice to transform directly into gas plumes that erupt in violent dust-filled jets.  

The ESA's Rosetta spacecraft, orbiting just 186 kilometers above the comet's irregular surface,, captured this powerful outgas blast on July 29, 2015, with its OSIRIS camera.  Vanishing in less than an hour, the plume originated from the craggy Anuket region on the comet’s narrow neck and was the brightest outburst seen from the Rosetta team.   During this period, the comet will also slough off chunks of ice ranging from one meter to 40 meters in diameter, forming part of the familiar shimmering cometary tail.   

One of the astonishing discoveries was that this intense jet created a temporary deflection of the solar wind surrounding the comet, causing a diamagnetic cavity, a rarely seen magnetic field-free region extending all the way out to the Rosetta probe.  Instruments aboard the craft also gathered data displaying compositional and structural changes in the comet's enveloping gas cloud, known as the coma.

Kathrin Altwegg, principal investigator for Rosetta's pressure sensor, ROSINA, commented on the observations:

This first ‘quick look’ at our measurements after the outburst is fascinating. We also see hints of heavy organic material after the outburst that might be related to the ejected dust. But while it is tempting to think that we are detecting material that may have been freed from beneath the comet’s surface, it is too early to say for certain that this is the case.

Comet 67P's activity will continue to increase in the weeks following perihelion, requiring the Rosetta spacecraft to duck for cover 300 kilometers above the surface to steer clear of shedding boulders and exploding gas jets. 

Are you impressed with its windy wonders during the comet's hot date with the sun?

(Via io9)


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