Stability of thin-shell interfaces inside compact stars

We use the thin-shell Darmois--Israel formalism to model and assess the stability of the interfaces separating phases, e.g., the core and the crust, within compact stars. We exemplify the relevance and non-triviality of this treatment in the simplest case of an incompressible star, in constant pressure phase transitions, and in the case of strange quark stars with crust.