Realism and applicability of stellar space-weather models

Develop and validate stellar space-weather models of winds, CMEs, and SEPs that address unresolved issues surrounding magnetic boundary conditions (e.g., incomplete Zeeman–Doppler Imaging maps), base thermodynamic parameters, coronal heating and wind acceleration mechanisms, and sparse observational constraints, and quantify the resulting uncertainties across stellar regimes.

Background

Extensions of solar wind/CME/SEP models to other stars rely on boundary conditions and assumptions that are poorly constrained (e.g., magnetic topology from ZDI, base density/temperature, heating prescriptions).

Improving model fidelity requires coordinated advances in observations (magnetism, winds, coronal diagnostics) and model formulation to capture stellar diversity and to support robust planetary impact assessments.

References

Despite this progress, there are still several open questions and issues that need to be addressed in order to improve the applicability and realism of these models for the stellar regime.

— The Exospace Weather Frontier  (2511.02871 - Loyd et al., 4 Nov 2025) in Section 3.3.4

Although we have shown in Paper~I that small-scale fields are important in coronal heating and reproducing coronal properties, it remains unclear to what extent they influence the global wind solution.

— High-Resolution Modelling of Coronae and Winds in Solar-type Stars with Varying Rotation Rates II. Stellar Winds  (2609.28067 - Chen et al., 23 Sep 2026) in Appendix A, Section Impact of Small-scale Magnetic Structures on Wind Modeling

The physical mechanism responsible for launching and accelerating winds from the surfaces of cool stars such as RSGs remains poorly understood.

— On the Origin of a Dusty Circumstellar Medium around Red Supergiants  (2608.28344 - Sujit et al., 28 Aug 2026) in Section 10, Discussion

Notably, this agreement is achieved using the steady stellar wind alone, without invoking any additional contribution from coronal mass ejections, whose role in angular-momentum loss remains debated \citep[e.g.,][]{Aarnio2012,Xu2024}.

— High-Resolution Modelling of Coronae and Winds in Solar-type Stars with Varying Rotation Rates II. Stellar Winds  (2609.28067 - Chen et al., 23 Sep 2026) in Section 4.3, Rotational Dependence of Angular-momentum Loss

Whether such ejecta escape the strong young-Sun field is debated, since an overlying large-scale field can confine weaker CMEs; the fast, massive events treated here are those that break out.

— Coronal Mass Ejections from the Young Sun: Deceleration-Powered Solar Energetic Particles as a Self-Extinguishing Forcing of the Early Earth  (2610.08758 - Panasenco, 6 Oct 2026) in Section 3, Section 3.1 (CME Deceleration and SEP Production)