2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/860We analyze cooling of neutron stars, assuming the presence of localized protons in the densest region of their cores. Choosing a single threshold density for proton localization and adjusting neutron star mass, we reproduce the observational data on effective surface temperatures of Vela and PSR 0656+14, with or without an accreted hydrogen envelope. However, the presence of a tiny hydrogen envelope is mandatory, in this model, for reproducing the Geminga data.5 pages, 3 figures, latex, uses aa.cls, to be published in Astronomy and AstrophysicsAstrophysicstext