Abstract

Poster - Splinter Activity

Chromospheric Activity Indicators in Visible Light and Near Infrared

P. Schöfer¹, A. Reiners¹ and the IAG CARMENES team^1
1Institut für Astrophysik, Georg-August-Universität Göttingen, Friedrich-Hund-Platz~1, 37077~Göttingen, Germany

Chromospheric activity imposes a challenge on high-precision radial velocity measurements and has therefore to be considered carefully by exoplanet hunters who are using the radial velocity method. CARMENES is searching for Earth-like planets around M dwarfs using two \'Echelle spectrographs which simultaneously cover wavelength ranges from 520 \AA to 960 \AA and 960 \AA to 17100 \AA. Using a spectral subtraction technique, we measure equivalent widths of several spectral lines that are sensitive to chromospheric activity in both the visible and the near infrared range. The sample size of \sim 300 M dwarfs and more than 7000 observations in total enables us to study correlations between the strengths of the different spectral lines for individual stars and across the M dwarf range, which we present on this poster.