Stellar Coronal Mass Ejections I. Estimating occurrence frequencies and mass-loss rates

TL;DR

This paper develops an empirical model to estimate stellar CME frequencies and mass-loss rates based on solar flare-CME relationships, revealing potential overestimations for active young stars and highlighting uncertainties in flare-CME associations.

Contribution

It introduces a new model linking solar flare-CME data with stellar flare rates to estimate stellar CME activity, addressing a gap in observational inference.

Findings

Modeled CME mass-loss rates may exceed observed rates for active stars.

Uncertainty in flare-CME association rates significantly affects estimates.

Possible suppression of CME rates in young stars due to stronger coronal confinement.

Abstract

Stellar coronal mass ejections (CMEs) may play an important role in mass- and angular momentum loss of young Sun-like stars. If occurring frequently, they may also have a strong effect on planetary evolution by increasing atmospheric erosion. So far it has not been possible to infer the occurrence frequency of stellar CMEs from observations. Based on their close relation with flares on the Sun, we develop an empirical model combining solar flare-CME relationships with stellar flare rates to estimate the CME activity of young Sun-like and late-type main-sequence stars. By comparison of the obtained CME mass-loss rates with observations of total mass-loss rates, we find that our modeled rates may exceed those from observations by orders of magnitude for the most active stars. This reveals a possible limit to the extrapolation of such models to the youngest stars. We find that the most uncertain component in the model is the flare-CME association rate adopted from the Sun, which does not properly account for the likely stronger coronal confinement in active stars. Simple estimates of this effect reveal a possible suppression of CME rates by several orders of magnitude for young stars, indicating that this issue should be addressed in more detail in the future.