The CARMENES Survey: A Search for Terrestrial Planets in the Habitable Zones of M Dwarfs

CARMENES (Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs) is a next-generation instrument under construction for the 3.5 m telescope at the Calar Alto Observatory by a consortium of eleven Spanish and German institutions. The scientific goal of the project is a five-year exoplanet survey targeting 300 M stars with the completed instrument. The CARMENES hardware consists of two separate échelle spectrographs covering the wavelength range from 0.55 to 1.7 μm at a spectral resolution of R = 82,000, fed by fibers from the Cassegrain focus of the telescope. Both spectrographs are housed in a temperature-stabilized environment in vacuum tanks, to enable a long-term radial velocity precision of 1 m s^-1 employing a simultaneous calibration with Th-Ne and U-Ne emission line lamps.