Wynn C. G. Ho, Kostas Glampedakis, Nils Andersson
We examine to what extent the inferred surface temperature of magnetars in
quiescence can constrain the presence of a superfluid in the neutron star core
and the role of magnetic field decay in the core. By performing detailed
simulations of neutron star cooling, we show that extremely strong heating from
field decay in the core cannot produce the high observed surface temperatures
nor delay the onset of neutron superfluidity in the core. We verify the results
of Kaminker et al., namely that the high magnetar surface temperatures require
heating in the neutron star crust, and crust heating is decoupled from
cooling/heating in the core. Therefore, because crust heating masks core
heating, it is not possible to conclude that magnetar cores are in a
non-superfluid state purely from high surface temperatures. From our interior
temperature evolutions and after accounting for proton superconductivity in the
core, we find that neutron superfluidity in the core occurs < a few x 100 yr
after neutron star formation. This onset time is unaffected by heating due to
core field decay at fields < 10^16 G. Thus all known neutron stars, including
magnetars, without a core containing exotic particles, should have a core of
superfluid neutrons and superconducting protons.
View original:
http://arxiv.org/abs/1112.1415
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