title: Rapid cooling of the neutron star in Cassiopeia A triggered by neutron superfluidity in dense matter.
abstract: We propose that the observed cooling of the neutron star in Cassiopeia A is due to enhanced neutrino emission from the recent onset of the breaking and formation of neutron Cooper pairs in the (3)P(2) channel. We find that the critical temperature for this superfluid transition is ≃0.5×10(9) K. The observed rapidity of the cooling implies that protons were already in a superconducting state with a larger critical temperature. This is the first direct evidence that superfluidity and superconductivity occur at supranuclear densities within neutron stars. Our prediction that this cooling will continue for several decades at the present rate can be tested by continuous monitoring of this neutron star.
authors.affiliation: Instituto de Astronomía, Universidad Nacional Autónoma de México, Mexico D.F. 04510, Mexico.
authors.forename: Dany
authors.initials: D
authors.lastname: Page
authors.forename: Madappa
authors.initials: M
authors.lastname: Prakash
authors.forename: James M
authors.initials: JM
authors.lastname: Lattimer
authors.forename: Andrew W
authors.initials: AW
authors.lastname: Steiner