A&A 383, 1076-1087 (2002)
DOI: 10.1051/0004-6361:20011797
Three types of cooling superfluid neutron stars: Theory and observations
A. D. Kaminker1, D. G. Yakovlev1 and O. Y. Gnedin21 Ioffe Physical Technical Institute, Politekhnicheskaya 26, 194021 St. Petersburg, Russia
2 Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218, USA
e-mail: yak@astro.ioffe.rssi.ru; ognedin@stsci.edu
(Received 21 November 2001 / Accepted 17 December 2001 )
Abstract
Cooling of neutron stars (NSs) with the cores composed of neutrons,
protons, and electrons is simulated assuming
1S
0 pairing of
neutrons in the NS crust, and also
1S
0 pairing of protons
and weak
3P
2 pairing of neutrons in the NS core, and using
realistic density profiles of the superfluid critical temperatures
. The theoretical cooling models of isolated
middle-aged NSs can be divided into three main types.
(I) Low-mass, slowly cooling NSs where the direct
Urca process of neutrino emission is either forbidden
or almost fully suppressed by the proton superfluidity.
(II) Medium-mass NSs which show moderate
cooling via the direct Urca process suppressed by
the proton superfluidity. (III) Massive NSs which show
fast cooling via the direct Urca process weakly suppressed by
superfluidity. Confronting the theory with observations
we treat RX J0822-43, PSR 1055-52 and RX J1856-3754
as slowly cooling NSs. To explain these sufficiently warm sources
we need a density profile
in the crust with a rather high and flat maximum and sharp wings.
We treat 1E 1207-52, RX J0002+62, PSR 0656+14, Vela, and
Geminga as moderately cooling NSs. We can determine
their masses for a given model of proton superfluidity,
, and the equation of state in the NS core.
No rapidly cooling NS has been observed so far.
Key words: stars: neutron -- dense matter
Offprint request: A. D. Kaminker, kam@astro.ioffe.rssi.ru
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