2017A&A...604A..50S

Context. The MgI 4571Å line and the b triplet are denoted in the literature as diagnostics of solar and stellar activity since their formation is in the low chromosphere.
Aims. We aim to investigate the potential of these four spectral lines as diagnostics of chromospheric activity in solar-like stars, studying the dependence of the intensity of these lines from local atmospheric changes by varying atmospheric models and stellar parameters.
Methods. Starting with Next-Gen photospheric models, we build a grid of atmospheric models including photosphere, chromosphere and transition region and solve the radiative transfer to obtain synthetic profiles to compare with observed spectra of main-sequence, solar like stars with effective temperatures in the range 4800-6400K, solar gravity and solar metallicity.
Results. We find that the MgI 4571Å line is significantly sensitive to local changes in the atmospheric model around the minimum temperature. Conversely, the lines of the b triplet do not show significant responses to changes on the local atmospheric structure.