We prove a Carleman estimate for a one-dimensional parabolic equation which degenerates at one extremity of the domain and has a bounded, time dependent coefficient multiplying the diffusion term. Then we use the estimate to show the null controllability of a coupled system characterized by this form of diffusion operator and bounded coefficients. • Carleman estimate is proved for a one-dimensional degenerate parabolic equation. • The second order operator may have a time-dependent bounded coefficient. • The form of our estimate is suitable to standard generalizations and adaptations. • Carleman estimate for a system of non-autonomous degenerate equations is obtained.
Gamboa et al. (Wed,) studied this question.