2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/170553We study the theta divisor of the compactified jacobian of a nodal, possibly reducible, curve. We compute its irreducible components and give it a geometric interpretation consistent with the classical Brill-Noether theory of smooth curves. Some applications on hyperelliptic stable curves are appended.36 pages. Final version, to appear in JEMSAlgebraic Geometry14H40, 14H51, 14K30, 14D20text