The cooling of a young bare strange star is studied numerically by solving
the equations of energy conservation and heat transport for both normal and
superconducting strange quark matter inside the star. We show that the thermal
luminosity from the strange star surface, due to both photon emission and e+e-
pair production, may be orders of magnitude higher than the Eddington limit,
for about one day for normal quark matter but possibly for up to a hundred
years for superconducting quark matter, while the maximum of the photon
spectrum is in hard X-rays with a mean energy of ~ 100 keV or even more. This
differs both qualitatively and quantitatively from the photon emission from
young neutron stars and provides a definite observational signature for bare
strange stars. It is shown that the energy gap of superconducting strange quark
matter may be estimated from the light curves if it is in the range from ~ 0.5
MeV to a few MeV.Comment: Ref [10] added and abstract shortened. 4 pages, 3 figures, revtex4.
To be published in Phys. Rev. Letter