NASA’s 3-D Study Of Comets Reveals Chemical Factory At Work b4in.org/g6xF A NASA-led team of scientists has created detailed 3-D maps of the atmospheres surrounding comets, identifying several gases and mapping their spread at the highest resolution ever achieved. [ Watch: HCN – Inner Coma Of C/2012 F6 (Lemmon) ] “We achieved truly first-of-a-kind mapping of important molecules that help us understand the nature of comets,” said Martin Cordiner, a researcher working in the Goddard Center for Astrobiology at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Cordiner led the international team of researchers. Almost unheard of for comet studies, the 3-D perspective provides deeper insight into which materials are shed from the nucleus of the comet and which are produced within the atmosphere, or coma. This helped the team nail down the sources of two key organic, or carbon-containing, molecules. The observations were conducted in 2013 on comets Lemmon and ISON using the Atacama Large Millimeter/submillimeter Array, or ALMA, a network of high-precision antennas in Chile. These comets are the first to be studied with ALMA. The ALMA observations combine a high-resolution 2-D image of a comet’s gases with a detailed spectrum at each point. From these spectra, researchers can identify the molecules present at every point and determine their velocities (speed plus direction) along the line-of-sight; this information provides the third dimension – the depth of the coma. “So, not only does ALMA let us identify individual molecular species in the coma, it also gives us the ability to map their locations with great sensitivity,” said Anthony Remijan, a scientist with the National Radio Astronomy Observatory, one of the organizations that operates ALMA, and a co-author of the study. The researchers reported results for three molecular species, focusing primarily on two whose sources have been difficult to discern (except in comet Halley). The 3-D maps indicated whether each molecule was flowing outward evenly in all directions or coming off in jets or in clumps. More b4in.org/g6xF
Posted on: Tue, 12 Aug 2014 20:35:05 +0000
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