Fast Cooling of Neutron Stars: Superfluidity vs. Heating and Accreted Envelope

Abstract

It is generally considered that the neutron star cooling scenarios involving fast neutrino emission, from a kaon or pion condensate, quark matter, or the direct Urca process, require the presence of baryon pairing in the central core of the star to control the strong neutrino emission and produce surface temperatures compatible with observations. I show here that within the kaon condensate scenario pairing is not necessary if: 1) the equation of state is stiff enough for the star to have a thick crust in which sufficient friction can occur to heat the star and 2) a thin layer, of mass larger than 10^{-12} Msol, of light elements (H and He) is present at the stellar surface. The effect of the light elements is to increase the heat flow and thus produce a higher surface temperature. Both the occurrence of heating and the presence of H and/or He at the surface (deposited during the late post-supernova accretion) can possibly be confirmed or infirmed by future observations.

7 pages AASLatex v4.0 + 2 ps figures. Submitted to Ap. J. Lett. ONLY change in this revised version is a misprint in a citation

References in corpus (3)

• Multiwavelength observations of isolated neutron stars as a tool to probe the properties of their surfaces
• Surface temperature of a magnetized neutron star and interpretation of the ROSAT data. II
• Strangeness in Stellar Matter

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• Thermal structure and cooling of superfluid neutron stars with accreted magnetized envelopes
• Prospects of Detecting Baryon and Quark Superfluidity from Cooling Neutron Stars
• Thermal structure and cooling of neutron stars with magnetized envelopes
• Constraints on Axion-like Particles and Nucleon Pairing in Dense Matter from the Hot Neutron Star in HESS J1731-347
• A Hot Water Bottle for Aging Neutron Stars
• Partially ionized hydrogen plasma in strong magnetic fields
• Constraining dense-matter superfluidity through thermal emission from millisecond pulsars
• Insights into the physics of neutron star interiors from pulsar glitches
• The magnetic structure of neutron stars and their surface-to-core temperature relation
• Discovery of an X-ray nebula around PSR J1718-3825 and implications for the nature of the gamma-ray source HESS J1718-385
• Thermal Evolution of Isolated Neutron Stars