CARMENES: Blue planets orbiting red stars
Cool low-mass stars (M dwarfs) are very interesting targets for searches for habitable planets. We are conducting a large survey of 300 nearby M dwarfs (average distance only 13pc), with the goal of finding terrestrial planets in their habitable zones. We have built a pair of spectrographs that are optimized specifically for measuring precise radial velocities of cool stars. This CARMENES instrument is now operational at the 3.5m telescope of Calar Alto Observatory in Spain, and 80% of the time on this telescope are currently allocated to the CARMENES M dwarf survey. During the first 18 months of operation, we have detected the signatures of several previously known or suspected planets as well as periodic signals that are likely new discoveries. At the same time, the CARMENES survey is generating a unique data set for studies of M star atmospheres, rotation, and activity.