Exoplanet habitability depends on a clearer picture of stellar flaring.

A white paper submitted to ESO's Expanding Horizons initiative calls for broader, high-cadence observations of stellar flares because many potentially habitable planets orbit active M dwarfs and flares can alter planetary atmospheres.

Astronomers are highlighting the need for better measurements of stellar flaring to assess exoplanet habitability. The concern focuses especially on M dwarfs (red dwarfs), which host many rocky planets and show frequent, energetic flaring. The paper argues that current spectroscopic information on flares from stars other than the Sun is sparse. The authors submitted their white paper to ESO's Expanding Horizons initiative to outline a path forward. Key facts: - The authors note that about 50 of roughly 70 exoplanets meeting a basic liquid-water temperature criterion orbit M-type stars, which are known for strong chromospheric activity including flares and coronal mass ejections. - High-energy flares can affect planetary atmospheres; past research is cited showing repeated strong flares can remove an ozone layer and increase surface exposure to ultraviolet radiation. - The white paper stresses the need for large-scale, continuous, time-domain observations of many stars and coordinated follow-up when flares occur, and it cites the Wide Field Survey Telescope as an existing example of the observational approach. Summary: The paper argues that without a much better empirical picture of flare frequency, energy, and spectral output across stellar types and ages, assessments of habitability for many nearby exoplanets remain limited. The authors have presented their proposal to ESO's Expanding Horizons initiative; further steps are undetermined at this time.