Portrait of a dynamic neighbour

Abstract

Brown dwarfs are celestial objects that lack the mass to become fully fledged stars. High-resolution maps of one such object add to the evidence that these exotic worlds have highly dynamic weather and climate. See Letter p.654 The recently discovered system known as Luhman 16AB is a binary consisting of two brown dwarfs — objects much bigger than planets but not big enough to become stars — and is a mere six light years from us. Only Alpha Centauri and Barnard's star are closer. Ian Crossfield et al. have now mapped the surface of brown dwarf Luhman 16B in the infrared and find large-scale surface patterns indicative of patchy clouds. Monitoring suggests that the characteristic timescale for the evolution of global weather patterns is about one day. Further observations of the evolution of weather patterns on brown dwarfs could provide a new benchmark for understanding how global circulation conditions affect dusty atmospheres on brown dwarfs and giant extrasolar planets.