Doppler spectroscopy
The CARMENES survey (Calar Alto high-Resolution search for M-dwarfs with Exoearths with Near-infrared and optical Échelle Spectrographs) is a project to examine approximately 300 M-dwarf stars for signs of exoplanets with the CARMENES instrument on Calar Alto's 3.5m telescope. Operating since 2016, it aims to find Earth-sized exoplanets around 2 (Earth masses) using Doppler spectroscopy (also called the radial velocity method).