The outer atmospheres of cool M dwarfs

众所周知，M矮星表现出非常不同的磁活动水平，表现在恒星黑子、X射线发射和-在光学波段-色球发射线上。为了更好地了解M矮星之间不同光谱亚型和活动水平的这些被加热的外层大气的物理性质，我们建议在这项基金申请的框架内对这些恒星进行一维和三维色球模拟。我们特别建议同时计算3D色球模型和1D色球模型，检查大气不均匀性是否可以用1D模型的单一或线性组合来解释，并将该模型与Carmenes获得的最新观测结果进行比较。因此，我们建议使用大气程序PHONIX来为M矮星构造一个经典的一维色球模型网格，并用用Carmenes光谱仪进行的高分辨率光谱观测来对抗我们的模型。对于选定的天体，我们建议对观测到的光谱和模拟的光谱进行详细的比较，以更好地描述选定单个恒星的色球物理特性。

M dwarfs are known to exhibit vastly different levels of magnetic activity, manifesting itself in star spots, X-ray emission and - at optical wavebands - chromospheric emission lines. In order to better understand the physics of these heated outer atmospheric layers for different spectral sub-types and activity levels among M dwarfs, we propose to perform 1D and 3D chromospheric modeling for these stars in the framework of this funding application. We specifically propose to compute both 3D chromospheric models and 1D chromospheric models and check, if the atmospheric inhomogeneities can be accounted for by single or linear combinations of 1D models, and juxtapose this modeling with state-of-the-art observations obtained by CARMENES. We therefore propose to use the atmosphere code PHOENIX for constructing a model grid of classical 1D chromospheres for M dwarfs and confront our modeling with high-resolution spectral observations taken with the CARMENES spectrograph. For selected objects we propose to perform a detailed comparison between observed and modeled spectra to better characterize the physics of the chromospheres of the selected individual stars.