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Ascertain whether rapid electron captures in SAGB O–Ne–Mg cores inevitably trigger dynamical collapse leading to electron-capture supernovae

Ascertain whether dynamical core collapse in super-asymptotic giant branch (SAGB) stars with oxygen–neon–magnesium (O–Ne–Mg) cores is inevitably triggered by rapid electron capture on 20Ne and 24Mg, and determine the conditions under which electron-capture-induced collapse occurs as opposed to alternative evolutionary outcomes.

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Background

Electron-capture supernovae are traditionally thought to arise from SAGB stars with O–Ne–Mg cores when rapid electron captures on 20Ne and 24Mg induce dynamical collapse. This channel has been used to explain low neutron star birth masses with relatively uniform outcomes.

However, the certainty of collapse in this channel has been questioned, introducing an unresolved issue that impacts predictions of minimum neutron star masses and the prevalence of electron-capture supernovae relative to low-mass iron core-collapse events.

References

In this narrow stellar evolution channel for stars around ∼9M⊙ in zero-age main sequence (ZAMS) mass, dynamical collapse is believed to occur after the formation of an O-Ne-Mg core in SAGB stars due to rapid electron capture (EC) on 20Ne and 24Mg 8–10, 22–25, different from iron core-collapse supernovae that undergo further hydrostatic burning stages and collapse only after iron core formation.

— The minimum neutron star mass in neutrino-driven supernova explosions (2407.08407 - Müller et al., 11 Jul 2024) in Introduction