CONICET | Buscador de Institutos y Recursos Humanos

One important clue to the physical mechanism of chromospheric heating inthe Sun is provided by the well-known widespread presence ofchromospheres in most cool stars. Recent UV observations are sheddingmore light into the characteristics of these chromospheres andtransition-regions. The physical modeling of these, combined with theolder, observations provides much less ambiguous constraints than the CaII line and other visible data could provide. We are building this newgeneration of models that are providing interesting trends that giveclues on the atmospheric parameters where physical mechanisms ofchromospheric and coronal heating operate.We will present some of thecurrent results and will point to some of the trends that are startingto emerge. This is of course an ongoing topic and much remains to belearnt.