Thermal Evolution of Hyperon-Mixed Neutron Stars

With the impressive amount of data that have poured out from Chandra and XMM/Newton X-ray space missions, as well as the lower energy band observations, we are now in the position where careful comparison of neutron star thermal evolution theories with observations will help us to distinguish among various competing theories. For instance, the latest theoretical and observational developments probably will contradict with the direct Urca cooling of neutron stars without some exotic particles. In this paper, we investigate one of the remaining possible fast cooling scenarios—direct Urca cooling of neutron stars in the hyperon-mixed phase. We conclude that this cooling scenario is a valid process if hyperon superfluidity is not too weak.