Name/Affiliation: F. J. Alonso-Floriano (UCM, Madrid)
Preparation of the CARMENES input catalogue. Low-resolution spectroscopy of M dwarfs
During the last three years, we have obtained low-resolution (R~1500) spectra of 754 M dwarfs and candidates with CAFOS at the 2.2 m Calar Alto telescope. They come from a number of sources (e.g., LÚpine & Gaidos 2011 stars fainter than J = 9 mag, new virtual observatory searches, stars with doubtful spectral typing, etc.). For all of them, we have derived spectral classes and types from comparison with standard stars and from all spectral indices defined in the literature and usable in our wide wavelength coverage from 430 to 830 nm. We have studied how our 31 measured indices vary with gravity, metallicity and activity. We have also measured pseudo-equivalent widths of the Halpha, Hbeta and Hgamma lines in emission, and related them to youth, multiplicity and other chromospheric activity indicators. The least active, brightest, latest M dwarfs are potential targets of CARMENES, the radial-velocity exoplanet hunter being built for the 3.5 m Calar Alto telescope.