What drives heavy mass loss in the final years before collapse? · revision history

Revision 2

Accepted · core change · record

Changes against revision 1:

Title
What drives heavy mass loss in the final years before collapse?
Plain
Many supernovae explode into thick gas that the star shed only years to decades before dying, far more than normal stellar winds can explain.
Precise · changed · core
Revision 1: Early spectra with narrow, short-lived emission lines (flash ionization) show dense circumstellar material within $\sim 1\mathrm{e}15\,\mathrm{cm}$ in a large fraction of Type II supernovae, implying mass-loss rates ~1e-4 to 1e-2 M_sun/yr in the last years, far above steady red supergiant winds of ~1e-6 M_sun/yr. Identify the mechanism (wave energy transport from core convection in the last burning stages, binary interaction, pulsation-driven winds) and whether it also produces observed pre-explosion outbursts. Answer: a mechanism predicting circumstellar mass and extent versus progenitor mass and evolutionary stage.
Revision 2: Early spectra with narrow, short-lived emission lines (flash ionization) show dense circumstellar material within $\sim 10^{15}\,\mathrm{cm}$ in a large fraction of Type II supernovae, implying mass-loss rates $\sim 10^{-4}$ to $10^{-2}$ $M_{\mathrm{sun}}/\mathrm{yr}$ in the last years, far above steady red supergiant winds of $\sim 10^{-6}$ $M_{\mathrm{sun}}/\mathrm{yr}$. Identify the mechanism (wave energy transport from core convection in the last burning stages, binary interaction, pulsation-driven winds) and whether it also produces observed pre-explosion outbursts. Answer: a mechanism predicting circumstellar mass and extent versus progenitor mass and evolutionary stage.
Settled by
Pre-explosion monitoring of many nearby supernova progenitors combined with early spectra, compared with predicted outburst timing and circumstellar masses.
Kind
phenomenon
Answer type
mechanism
References
(empty)
Literature status
open
Status note
2023: SN 2023ixf in M101, the nearest Type II supernova in a decade, showed dense, confined circumstellar material.
Posed since
(empty)

Decisions