(Astronomy)
Astronomy Article: Ultraviolet study reveals surprises in Rosetta comet coma
Reference and link to article: http://www.astronomy.com/news/2015/06/ultraviolet-study-reveals-surprises-in-rosetta-comet-coma
Astronomy terms used in article and explanations of connections
Electromagnetic radiation (UV): a form of radiant energy released by electromagnetic processes
Comet (and parts thereof): a celestial object consisting of a nucleus or ice and dust, also having a tail.
Perihelion: the point in the orbit of a celestial body at which it is closest to the sun
Subatomic particles: particles smaller than the atom
Alice Spectrograph: records various spectra
Electromagnetic radiation (UV): a form of radiant energy released by electromagnetic processes
Comet (and parts thereof): a celestial object consisting of a nucleus or ice and dust, also having a tail.
Perihelion: the point in the orbit of a celestial body at which it is closest to the sun
Subatomic particles: particles smaller than the atom
Alice Spectrograph: records various spectra
Summary and Opinion of Article
The article is about a study conducted using the Rosetta spacecraft which revealed that electrons are responsible for the rapid breakup of water and carbon dioxide from the surface of Comet 67/Churyumov-Gerasimenko.
The Alice spectrograph detects ultraviolet wavelengths and from this, scientists are able to deduce the chemical composition of the coma. ESA’s Rosetta mission reached the comet last year in August; regarding this study, the team focused on the nature of plumes of water and carbon dioxide gas erupting from the surface of the comet. These eruptions are triggered by photons emitted from the sun. These plumes are caused by the degradation of the molecules into their constituents close to the comet’s nucleus as illustrated in the diagram below. This study is rather important as it demonstrates the importance of going to comets to observe them close-up. In this case, observing the comet closely allowed scientists to deduce that they were directly observing the parent molecules being broken up by electron in a 1 km vicinity by analysis of the relative intensities of observed atomic emissions. However, without close-up observation such as this, scientists would only be able to see the atomic constituents after their parent molecules have been broken by sunlight, hundreds to thousands of miles away from the nucleus of the comet. |
Photon from sun hits water molecule in the coma, ionizing it, knocking out an electron. This electron then hits another water molecule, breaking it into its constituents as well as energizing them. These atoms then emit UV light detected by Rosetta’s Alice instrument. A similar process occurs with electrons and carbon dioxide molecules.
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