End-States of Evaporation Under a Density Cap: A Classification by Initial Mass

The remnant boundary sits at 8.659e+10 kilograms and the expiring-today boundary at 1.730e+11 kilograms. An object starting at the second boundary radiates 7.766e+27 joules over its life and returns a fraction 4.995e-01 of its mass, retaining only the remnant. The two boundaries are separated by only a factor of about two, a striking compression: because the remnant mass is so heavy, an object must start within a factor of two of the expiring-today mass to finish evaporating at all, and it then retains about half of its initial mass in the remnant. Any primordial population formed below the expiring boundary but above the remnant boundary is therefore a remnant population today, and it kept roughly half of the mass it started with. The classification converts a qualitative story into an accounting tool. Computed from stated assumptions, not measured.