2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/121490Trapping of neutrinos in extremely compact stars containing trapped null geodesics is studied. We calculated the ratio of produced to trapped neutrinos in the simplest model of uniform density stars. This gives the upper limit on trapping coefficients in real objects.3 pages, 2 figures, to appear in "Proceedings of the 11th Marcel Grossmann Meeting on General Relativity", eds H. Kleinert, R. T. Jantzen, R. RuffiniAstrophysicstext