Stellar Coronal Mass Ejections with HWO: A Science Case Concept

TL;DR

This paper advocates for incorporating stellar coronal mass ejection detection into the Habitable World Observatory's design to better understand their impact on planetary biosignatures like ozone.

Contribution

It presents a conceptual framework for HWO to detect CMEs and assess their effects on biosignatures, influencing future telescope design considerations.

Findings

HWO should detect CMEs causing 10% ozone depletion at less than one per decade.

Coronal dimming is the most thoroughly explored CME detection method.

Multiple detection methods like coronal dimming, Doppler shifts, imaging, and aurora are considered feasible.

Abstract

The primary mission of the Habitable World Observatory (HWO) will be to constrain the prevalence of life on Earth-like planets. These planets will be subject to impacts by energetic particles generated from coronal mass ejection (CME) shocks that can dramatically deplete ozone, a key biosignature gas. Other biosignatures are also likely vulnerable, though not yet studied. Here, we make a conceptual case for factoring sensitivity to stellar coronal mass ejections into the design of HWO. We drive design considerations by requiring that HWO constrain the rate of CMEs producing 10% or greater depletions of total ozone column to fewer than one per decade, the timescale over which ozone returns to pre-event levels. As CME detection methods, we consider coronal dimming, doppler shifted emission, high contrast imaging, and planetary aurora. We explore coronal dimming most thoroughly of the four, though with appropriate design considerations each of these may be possible with HWO.