Stellar magnetic activity shapes the space environment that exoplanets must endure—both radiative, through coronal X-rays, and particle-based, through stellar winds, coronal mass ejections (CMEs), and the energetic particles (EPs) these events accelerate. Using the Alfvén Wave Solar-atmosphere Model using convective-dynamo-generated magnetic maps as input, we simulate the coronae and 3D winds of four young solar-type stars plus the Sun, spanning rotation periods from 1 to 27 days and surface field strengths of roughly 6 to 1200 G. This is the first physically driven, 3D global model to treat the X-ray corona and stellar wind of solar-type stars self-consistently. The resulting framework yields a self-consistent activity–wind relation: the mass loss rate scales with surface X-ray flux as a power law of index ~0.67. Furthermore, we carry out the first global 3D MHD-driven,CME-shock-triggered stellar EP simulation for an active young Sun, EK Draconis. Its CMEs are two to four orders of magnitude more energetic than the Sun's. However, the resulting >10 MeV proton flux at the habitable zone exhibits considerable scatter and mostly remains within the solar range. This result challenges the long-standing practice of extrapolating stellar EP fluxes from the solar flare–EP scaling law. Together, these findings connect X-ray radiation and particles, providing physically grounded space-weather inputs for studies of exoplanet habitability. Speaker: Yue-Hong Chen
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