Mass loss and circumstellar environments of supernovae

Determine the mechanisms driving mass loss in massive stars, characterize the elemental abundance and ionization of supernova circumstellar media, establish the diversity of ultraviolet supernova spectra, quantify the contribution of ultraviolet emission to the shock-power budget of circumstellar-interacting supernovae, and determine the interstellar-medium properties of supernova host environments.

Background

Early ultraviolet spectroscopy of circumstellar-interacting supernovae can reveal narrow emission and absorption lines produced by the progenitor wind. These features encode the density, ionization, composition, and mass-loss history of the circumstellar medium shortly before explosion.

The paper notes that high-resolution early-time UV observations are largely unavailable because of limitations in sensitivity, cadence, and target-of-opportunity access. A future UV spectrograph could resolve these features and connect progenitor mass loss to supernova diversity and shock energetics.

References

High-resolution, UV spectroscopy of SNe with instruments that have higher sensitivity than HST will enable fundamental questions to be answered about the origins and properties of CSM-interacting SNe: What mechanisms drive mass-loss in massive stars? What is the elemental abundance and ionization of CSM in SNe? What is the UV spectral line diversity of SNe? How does UV emission contribute to the shock power budget of SNe interacting with CSM? What are the ISM properties of SN host environments?

— The future of high-resolution UV spectroscopy: Science with a UV Échelle spectrograph on the Habitable Worlds Observatory, or a dedicated mission  (2609.09329 - Cia et al., 8 Sep 2026) in Section 4, subsection “Supernovae,” under “The Future of Supernova UV Spectroscopy”