REDA, RAFFAELERAFFAELEREDAGIOVANNELLI, LUCALUCAGIOVANNELLIALBERTI, TOMMASOTOMMASOALBERTIFrancesco BerrilliBertello, LucaLucaBertelloDEL MORO, DARIODARIODEL MORODi Mauro, Maria PiaMaria PiaDi MauroGiobbi, PiermarcoPiermarcoGiobbiValentina Penza2025-01-032025-01-0320230035-8711http://hdl.handle.net/20.500.12386/35602The Earth's magnetosphere extension is controlled by the solar activity level via solar wind properties. Understanding such a relation in the Solar System is important for predicting also the condition of exoplanetary magnetospheres near Sun-like stars. We use measurements of a chromospheric proxy, the Ca II K index, and solar wind OMNI parameters to connect the solar activity variations, on the decennial time scales, to the solar wind properties. The data span over the time interval 1965-2021, which almost entirely covers the last 5 solar cycles. Using both cross-correlation and mutual information analysis, a 3.2-year lag of the solar wind speed with respect to the Ca II K index is found. Analogously, a 3.6-year lag is found once considering the dynamic pressure. A correlation between the solar wind dynamic pressure and the solar UV emission is found and used to derive the Earth's magnetopause standoff distance. Moreover, the advantage of using a chromospheric proxy, such as the Ca II K index, opens the possibility to extend the relation found for the Sun to Sun-like stars, by linking stellar variability to stellar wind properties. The model is applied to a sample of Sun-like stars as a case study, where we assume the presence of an Earth-like exoplanet at 1 AU. Finally, we compare our results with previous estimates of the magnetosphere extension for the same set of Sun-like stars.STAMPAenArticle10.1093/mnras/stac38252-s2.0-85160209090https://academic.oup.com/mnras/article/519/4/6088/6973223http://arxiv.org/abs/2203.01554v22023MNRAS.519.6088RFIS/05 - ASTRONOMIA E ASTROFISICA