![School of Natural Sciences Event](/sites/default/files/styles/two_column_medium/public/2019-09/sns_default.jpg?itok=IEu1CLXj)
Princeton Center for Heliophysics Seminar
Modeling CME-driven Solar/Stellar Energetic Particle Events at Solar-like Stars
Coronal mass ejections (CMEs) and solar flares are arguably the two most energetic phenomena in the solar system. Large gradual solar energetic particle (SEP) events are primarily associated with coronal mass ejections (CME) driven shocks. The Discovery of frequent superflares on active cool stars opened a new avenue in understanding the properties of eruptive events and their impact on exoplanetary environments. Solar data suggest that CMEs should be associated with superflares on active solar-like planet hosts and produce Stellar Energetic Particle (StEP) events that could be orders of magnitude stronger than solar events.
The improved Particle Acceleration and Transport in the Heliosphere (iPATH) model is a physics-based MHD SEP model developed at CSPAR. The iPATH model simulates diffusive shock acceleration (DSA) at CME-driven shocks and follows the subsequent transport of energetic particles through the inner heliosphere. Our recent work applies previous modeling efforts using iPATH for SEP events in the solar system to the stellar energetic particle events at young solar-like stars. We derive the scaling of StEP’s fluence and hardness of energy spectra with CME speed and associated flare energy. This study focuses on the very high energy (~hundreds of MeVs to GeVs) particles and their impact on erosion and chemistry of exoplanetary atmospheres. These results will have crucial implications for the prebiotic chemistry and expected biosignatures from atmospheres of early Earth and young rocky exoplanets, as well as the chemistry and isotopic composition of circumstellar disks around infant Suns.