Stellar properties of M dwarfs

The stellar parameters of M dwarfs in our sample have been determined by comparing the high resolution spectra both in the optical and in the near-infrared simultaneously observed by CARMENES with the synthetic spectra obtained from the BT-Settl model atmosphere. The detailed spectral synthesis of these observed spectra both in the optical and in the near-infrared helps to understand the missing continuum opacity. For the first time, we derive fundamental stellar parameters of M dwarfs using the high resolution optical and near-infrared spectra simultaneously.

We determine Teff, logg and [M/H] for 292 M dwarfs of spectral type M0 to M9, where the formation of dust and clouds are important. The derived Teff for the sample ranges from 2300 to 4000K, values of log g ranges from 4.5<=logg<=5.5 and the resulting metallicity ranges from -0.5<=[M/H]<=+0.5. We have also explored the possible differences in Teff, logg and [M/H] by comparing them with other studies of the same sample of M dwarfs.