Pluto's chemistry

It might be that astronomers no longer consider Pluto to be a fully fledged planet but that does not make it of any less interest to chemists. Now, the highly sensitive Cosmic Origins Spectrograph on board the Hubble Space Telescope has revealed a strong UV absorber on Pluto's surface. The spectrum offers new evidence that there are either complex hydrocarbons and/or nitrile molecules on the surface. These compounds might provide a chemical explanation for Pluto's ruddy coloration.