# # Program information file # PROGRAM_ID 2023B091 PROGRAM_TITLE Star spots physics across the HR diagram. PROGRAM_INV1 Guillaume Huber PROGRAM_INV2 Haosheng Lin PROGRAM_INV3 PROGRAM_INV4 PROGRAM_INV5 PROGRAM_SCICAT stellar PROGRAM_ABSTRACT_BEG The discovery of super flares on G type stars with flare energy far exceeding those of solar flares suggests that the spots on these superflaring stars are very different from sunspots. This proposal aims to use high resolution atomic and molecular spectra to study the magnetic and thermodynamic properties of star spots across the HR diagram. These information, coupled with size of the spots and rotation speed of the stars [inferred from light curves] and spatially resolved observations of flares on the sun, should provide a comprehensive picture of the star spot formation mechanism, leading to better understanding of the flare phenomenon on both the sun and beyond. PROGRAM_ABSTRACT_END