Poster Abstracts

Name/Affiliation:  Vasco Neves (Universidade Federal do Rio Grande do Norte)

Title:  A new Fe/H] and Teff calibration for M dwarfs in the visible: a high-precision tool to explore the star-planet relation

We present a new technique to obtain high precision determinations of metallicity and effective temperature of M dwarfs in the optical. Our method makes use of the information of most lines in the 550-690 nm spectral region of HARPS spectra. It consists in the measurement of pseudo equivalent widths and their correlation with established scales of metallicity and effective temperature. The calibration achieves a $rms$ of 0.08 dex for [Fe/H], 110 K for $T_{eff}$, and is valid in the (-0.89, 0.25 dex), (2650, 3900 K), and (K7, M5.5) intervals for [Fe/H], Teff and spectral type respectively. We also calculated the RMSE$_{V}$ which estimates uncertainties of the order of 0.12 dex for the metallicity and of 310 K for the effective temperature. Our calibration is available online at We used our calibration to study the star-planet relation of Giant and Neptunian planets around M dwarfs. We confirm the Giant planet-metallicity relation, already discovered for FGK dwarfs, as well as the non-existence of such a correlation for Neptunian hosts. We also plan to use this new high-precision calibration to constrain evolutionary and transit light curve models in order to obtain more precise values of stellar and planetary mass and radius.