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An accretion outburst onto a neutron star deposits hydrogen-rich and/orhelium-rich material into the neutron star's envelope. Thermonuclear burning ofaccreted material robustly produces Urca pairs\textrm{---}pairs of nuclei thatundergo cycles of $e^-$-capture and $\beta ^-$-decay. The strong $T^5$dependence of the Urca cooling neutrino luminosity means that Urca pairs in theneutron star interior potentially remove heat from accretion-driven nuclearreactions. In this study, we identify Urca pairs in the neutron star's ocean\textrm{---} a plasma of ions and electrons overlaying the neutron star crust\textrm{---} and demonstrate that Urca cooling occurs at all depths in theocean. We find that Urca pairs in the ocean and crust lower the ocean'ssteady-state temperature during an accretion outburst and that unstable carbonignition, which is thought to trigger superbursts, occurs deeper than it wouldotherwise. Cooling superburst light curves, however, are only marginallyimpacted by cooling from Urca pairs because the superburst peak radiativeluminosity $L_{\rm peak}$ is always much greater than the Urca pair neutrinoluminosity $L_{\nu}$ in the hot post-superburst ocean.

Urca cooling pairs in the neutron star ocean and their effect on superbursts