Constraining a possible time-variation of the gravitational constant through "gravitochemical heating" of neutron stars

A hypothetical time-variation of the gravitational constant G would produce gravitochemical heating of old (≳ 10^7-8 yr) neutron stars. It could produce detectable thermal ultraviolet emission from such stars for changes as small as |Ġ/G|~ 10^-12 yr^-1, comparable to the best existing upper limits from other methods.