One Year in the Life of Young Suns: Data Constrained Corona-Wind Model of kappa1 Ceti

TL;DR

This study develops a 3D MHD model constrained by observational data to simulate the coronal environment of the young star kappa1 Ceti, revealing significant variations in stellar wind and magnetic activity that impact exoplanet atmospheres.

Contribution

The paper introduces a data-constrained 3D MHD model of a young star's corona, capturing its magnetic and wind evolution over a year, which aids in understanding exoplanet atmospheric erosion.

Findings

Stellar corona transitioned from simple dipole to tilted multipole over a year.

CIRs exert dynamic pressure 1300 times greater than the Sun's, affecting planetary atmospheres.

Model provides realistic inputs for exoplanet atmospheric studies.

Abstract

The young magnetically active solar-like stars are efficient generators of ionizing radiation in the form of X-ray and Extreme UV (EUV) flux, stellar wind and eruptive events. These outputs are the critical factors affecting atmospheric escape and chemistry of (exo)planets around active stars. While X-ray fluxes and surface magnetic fields can be derived from observations, the EUV emission and wind mass fluxes, Coronal Mass Ejections and associated Stellar Energetic Particle events cannot be directly observed. Here, we present the results of a three-dimensional magnetohydrodynamic (MHD) model with inputs constrained by spectropolarimetric data, HST/STIS Far UV, X-ray data data and stellar magnetic maps reconstructed at two epochs separated by 11 months. The simulations show that over the course of the year, the global stellar corona had undergone a drastic transition from a simple dipole-like to a tilted dipole with multipole field components, and thus, provided favorable conditions for Corotating Interaction Events (CIRs) that drive strong shocks. The dynamic pressure exerted by CIRs are 1300 times larger than those observed from the Sun and can contribute to the atmospheric erosion of early Venus, Earth, Mars and young Earth-like exoplanets. Our data-constrained MHD model provides the framework to model coronal environments of G-M planet hosting dwarfs. The model outputs can serve as a realistic input for exoplanetary atmospheric models to evaluate the impact of stellar coronal emission, stellar winds and CIRs on their atmospheric escape and chemistry that can be tested in the upcoming JWST and ground-based observations.