2026ApJ...998..128Z

In low-mass core-collapse supernova (SN) progenitors, nuclear burning beyond oxygen can become explosive under degenerate conditions, triggering eruptive mass loss before the final explosion. We investigate such pre-SN eruptions using SNEC hydrodynamic simulations and realistic stellar models, parameterizing the nuclear energy deposition as a fraction of the binding energy of the combined He layer and H-rich envelope. For the lowest-mass model (9M_⊙), the ejecta mass (M_ej) scales with the energy gained by the H-rich envelope via a power law (index ∼ 3.5). Across 9-10M_⊙, this relation shows limited scatter within a factor of ∼2.6, enabling an estimation of the gained energy from M_ej. The shock passage also flattens the bound envelope, which can affect the SN light-curve morphology and provide another diagnostic for the eruption. Then, we compute the associated precursor light curves for the 9M_⊙model with the multigroup radiative-transfer code STELLA. These signals are typically faint, with bolometric luminosities of ∼10³⁹ erg lasting hundreds of days. Their cool blackbody spectra make them brighter in the infrared yet several magnitudes fainter than observed pre-SN precursors at the threshold for full envelope ejection. To aid future studies, we make our posteruption stellar profiles and precursor light curves publicly available.