  We study the systematics of neutron star cooling curves with three
representative masses from the most populated interval of the estimated mass
distribution for compact objects. The cooling simulations are made in the
framework of the nuclear medium cooling (NMC) scenario using different
combinations of possible nucleon-nucleon pairing gaps. Possible heating or
enhanced cooling mechanisms in the crust are not considered. We define a
constraint on the highest possible temperatures for a given age of young
neutron stars and show that this limits the freedom of modeling pairing gaps
and crust properties.
