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The characterization of exoplanets conditions cannot be based solely on the knowlegde of the planetary main parameters, since the properties and the activity level of the host star, as well as the effects of extreme space weather phenomena, need also to be considered. Here we propose a synergic strategy based both on an asteroseismic approach and a space weather/space climate analysis. By studying the oscillation spectra it is possible to derive the host star fundamental parameters, including a precise determination of the age. Combining this informations with those coming from observations in the UV spectrum of the star (Ca II H & K lines), and by using relations which we have already calibrated on the Sun (Reda et al. 2021 submitted), we are able to estimate the mean stellar wind acting on the exoplanets, enabling to estimate the erosion of their atmospheres. The best targets for this approach consists of terrestrial planets orbiting around solar-like stars, which are exactly the primary target of the PLATO mission.

Solar variability related to its magnetic activity can be quantified by using synthetic indices (e.g. sunspots number) or physical ones (e.g. chromospheric proxies). In order to connect the long-term solar activity variations to solar wind properties, we use Ca II K index and solar wind OMNI data in the time interval between 1965 and 2019, which almost entirely coverthe last 5 solar cycles. A time lag in the correlation between the parameters is found. This time shift seems to show a temporal evolution over the different solar cycles. The advantage to use a chromospheric proxy opens the possibility to extend the relation found for the Sun to link stellar variability and stellar wind properties in Sun-like stars.