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Accepted · first revision · record

Title: Which massive stars explode and which collapse quietly to black holes?
Plain: Some massive stars may vanish into black holes without an explosion; which ones do is unknown.
Precise: Map the outcome (explosion leaving a neutron star, fallback black hole, or failed supernova with direct black hole formation) against pre-collapse core structure (compactness parameter xi_2.5, iron-core mass, Ertl two-parameter criterion) for initial masses $8 \text{ to } 120\,M_{\mathrm{sun}}$. Answer: an outcome map from 3D simulations validated against the absence of observed red supergiant progenitors above $\sim 17-18\,M_{\mathrm{sun}}$ and against disappearing-star searches.
Settled by: Agreement between simulated outcome maps and a statistical sample of failed-supernova candidates and measured progenitor masses.
Kind: well-posed
Answer type: classification
References: (empty)
Literature status: open
Status note: 2026: the disappearance of the massive hydrogen-depleted star M31-2014-DS1 in the Andromeda galaxy was published as a failed supernova forming a black hole.
Posed since: 2009