The stellar content of eROSITA

Stars make up a large fraction of the sources detected by eROSITA, only rivaled by AGN. This large number of new X-ray detections provides us with the means to study, for the first time, statistically robust samples that are homogeneous in their intrinsic stellar properties. Such a novel approach is expected to reveal the internal workings of stellar X-ray emission in particular and of stellar magnetic activity in general when combined with data from other large scale surveys. In this contribution, I will (1) present our fully Bayesian scheme to extract the stellar content in the eROSITA all-sky survey, how it uses information from other all-sky surveys like Gaia, and how it differs from the approaches used for the other source categories, (2) provide an initial assessment of the stellar X-ray properties in terms of X-ray luminosity distribution functions, spatial stratification, and how ground-based surveys like 4Most or SDSS enrich the X-ray data, and (3) will present results from our PV program, a deep scan of the nearby eta Chamaeleontis cluster, and demonstrate how eROSITA will be used to derive cluster memberships and thereby the early stellar evolution with direct impacts on the how planets evolve.