Multiplicity of cool dwarfs

Multiple systems have long been used to probe the origin and evolution of stars of all masses. Only in the past 10–15 years have such studies been extended to brown dwarfs and the lowest mass stars through binary surveys of both young star forming regions and the older field population. In addition, a groundswell of interest in M dwarfs in recent years has resulted in large, modern datasets for these most common stars in the Galaxy, thereby enabling renewed perspectives on their multiplicity properties. These latest observational results have in turn fueled the many theories competing to explain the formation of low‐mass stars and brown dwarfs. This Cool Stars 17 splinter session examined the current state of this field by reviewing results from the numerous observational techniques – radial velocities, astrometry, direct imaging, and synoptic surveys – that have been used to study multiplicity from the earliest embedded protostars to objects in young star forming regions, old and intermediate‐age clusters, as well as the more heterogeneous field population. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)