Understanding neutron stars from the outside in, Andrew Cumming (McGill University)

Neutron stars are unique laboratories for studying high density matter. Recent observations of neutron stars cooling after long accretion events have focused attention on the neutron star crust. In this talk, I discuss our current understanding of the physics of the neutron star crust, and how it can be tested with observations of transiently accreting neutron stars. Observed cooling times are giving us direct evidence that the neutrons in the crust are superfluid, as well as constraining the thermal conductivity.  Whereas previous work assumed a single nuclear species at each depth in the crust, these observations are forcing us to take a new look at the structure and composition of the crust when multiple nuclear species are present.