Different gases radiate at different wavelengths, revealing themselves as different colors in the images generated by Rosetta's various cameras. Photo by ESA/Rosetta/University of Maryland
NATIONAL HARBOR, Md., Nov. 12 (UPI) -- Comet 67P is now moving away from its apogee with the sun. As it does so, it's shedding less and less gas and debris. But for a while there, it was pretty gassy.
All the while, the European Space Agency's Rosetta probe, and its Optical, Spectroscopic and Infrared Remote Imaging System cameras, have been eyeing the comet's gas jets.
Recently, a team of scientists at the University of Maryland used the OSIRIS data to map the different types of gases beings expelled by 67P. The result is a variety of colorful images revealing the unique presence of various gases.
As water and hydrogen cyanide molecules trapped in the comet escape through gaps in its melting ice, they're broken down by ultraviolet radiation from the sun. Water becomes hydrogen and oxygen, and hydrogen cyanide becomes, you guessed it, hydrogen and cyanide.
These gases give off different wavelengths, allowing them to be picked up separately by Rosetta's various cameras. Oxygen becomes excited enough to emit its own photons; it doesn't have to wait to absorb them from the sun. This is helpful for scientists working to track the presence of water in, on and around the comet.
"Because Rosetta is very close to the comet, it can observe gas much closer to the nucleus than can be seen from Earth," Dennis Bodewits, an assistant research scientist in astronomy at Maryland, said in a press release. "This has already revealed unanticipated physical processes that are important both in breaking apart the original molecules of gas and in causing the fragments to shine."
Bodewits presented the teams findings this week at the 47th annual meeting of the American Astronomical Society's Division for Planetary Sciences, currently being held outside of Washington, D.C.
When researchers first started looking at the comet's gas emissions, they found more than they expected. But as the comet moved closer to the sun, Rosetta's observations and their predictions have come into closer agreement.