This week we discussed the discovery of an extrasolar planet orbiting the star Fomalhaut, 25 light-years from Earth. The planet was discovered from Hubble Space Telescope images taken over a few years where the planet could be seen moving in a motion appropriate for a body orbiting the star. The authors rule out other possibilities, such as a brown dwarf with a proper motion that made it appear to orbit Fomalhaut.
Paper: Optical Images of an Exosolar Planet 25 Light Years from Earth, Science, 322, 1345, 2008.