A change in the relationship between chromospheric activity and the large-scale magnetic field for G stars on the main sequence

Abstract

International audienceWe present a database of chromospheric activity and magnetic field strengths for 954 F-M dwarf stars Our active sample complements previous chromospheric activity surveys that usually focus on inactive, planet search targets. The internal magnetic fields of cool stars are known to power activity in stellar chromospheres, but there is still much to learn about the nature of this relationship and its dependence on stellar properties. We draw on data from PolarBase, a rich legacy database of observations from the spectropolarimeters ESPaDOnS (CFHT) and NARVAL (TBL), to survey the chromospheric activity and large-scale magnetic field strengths for 954 F-M dwarf stars