Puzzling comet composition solved?
For years comets have mystified scientists with their compositions that appear to have formed in both warm and cold environments, rather than in one location of a uniform temperature. But new research shows that the reason some comets feature patches of differing surface composition is not because they are made from material that formed in different parts of the Solar System, but because some parts of their surface absorb heat at varying rates. This leads to localized heat sinks and cold traps, according to a new model constructed by David Jewitt and Aurelie Guilbert-Lepoutre from the University of California, Los Angeles (UCLA). Their model shows that the chemical composition of a comet can evolve in the ten million year period during which a comet is classed as a Centaur, migrating from the Kuiper Belt to the inner Solar System.