Proto-Neutron Star Mass Growth and the Threshold for Failed Supernovae

Some massive stars collapse to black holes without a bright explosion. A useful first diagnostic is whether continued accretion pushes the hot remnant past the maximum mass that pressure can support once it cools. This paper builds a transparent accretion-growth estimate and locates the progenitor mass at which the remnant crosses the cold ceiling under stated assumptions. Using the calculation described in the Methods, the headline results are: Mmax_cold_Msun = 2.16, first_failing_Mprog_Msun = 28, Macc_40_Msun = 2.62. Under the stated scaling the crossing occurs near the middle of the massive-star range, and the most massive progenitors overshoot by a substantial amount. The threshold is sensitive to the fallback allowance at the level of several solar masses in progenitor mass, which explains why different simulation groups place the boundary of explodability at different locations while agreeing on the underlying mechanism. This study is simulated and computed from stated assumptions; it is not a measurement. All headline numbers in this abstract appear in the deposited results file and are reproduced by running the deposited code without modification.