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.
@article{arxiv.2604.16746,
title = {Stellar Coronal Mass Ejections with HWO: A Science Case Concept},
author = {R. O. Parke Loyd and James Paul Mason and Ivey Davis and Kevin France and Meng Jin and Karin Dissauer},
journal= {arXiv preprint arXiv:2604.16746},
year = {2026}
}
Comments
17 pages, 2 figures, 5 tables. Version 2 adds 15 endorsers and a paragraph on CME-SEP models. Endorsements will continue to be accepted via https://forms.gle/YByK22Yj47NMEPbp8 until 2026 July 15