Recent Progress in Data Constrained Sun-as-a-Star Modeling of Coronae, Winds and Eruptive Events of Young Solar-Like Stars
Abstract
Discovery of over 4700 exoplanets in our Galaxy suggests that close-in rocky exoplanets in the habitable zones around magnetically active G, K and M dwarfs should be exposed to high stellar coronal X-ray and Extreme UV (EUV) and wind mass fluxes. Kepler and TESS missions have revealed frequent superflares on cool G, K and M planet hosting dwarf stars, providing a mechanism by which host stars may have profound effects on the physical and chemical evolution of exoplanetary atmospheres. Solar observations indicate that energetic flares are usually accompanied by ejection of coronal magnetized plasma referred to as coronal mass ejections or CMEs. As CMEs propagate out from the solar corona into interplanetary space, they drive shocks. Shocks are the sites of efficient acceleration of solar energetic particles (SEPs) to GeV energies. SEPs can penetrate (exo)planetary atmospheres and cause significant changes in atmospheric chemistry. While stellar superflares can be directly observed and characterized in X-ray, FUV/UV, optical and radio bands, the signatures of their CME and SEP counterparts remain elusive and need detail theoretical modeling. The major questions this leads to are: Can we extend solar models to simulate energetic environments of young solar type stars? Can we relate and scale the properties of solar/stellar superflares & associated CMEs with the fluence and particle energy spectra from active K and M dwarfs? Here, I will review the recent Sun-as-a Star observations of sunspots and associated active regions in optical, FUV, EUV and X-ray bands and their implications for stellar active regions from active stars. I will describe our recent multi-observatory international project "Magnetic Lives of Young Suns" that coordinates HST-XMM-Newton, TESS, NICER and ground-based observations taken with CFHT observations of young (0.1-0.6 Gyr) solar-like (G and K type) dwarfs. These data provide critical inputs to the data-constrained three-dimensional (3D) fully thermodynamic magnetohydrodynamic (MHD) models of coronae, and winds from young solar-like stars. I will then present recent results of data-constrained 3D MHD models of superlares and CMEs from young solar-like stars coupled to the kinetic models of SEP events, the crucial factor for understanding of the rise of the feedstock molecules of life on early Venus, Earth Mars and young rocky exoplanets.
- Publication:
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44th COSPAR Scientific Assembly. Held 16-24 July
- Pub Date:
- July 2022
- Bibcode:
- 2022cosp...44.2471A