Thursday, April 25, 2013

1304.6546 (Jose A. Pons et al.)

Too much "pasta" for pulsars to spin down    [PDF]

Jose A. Pons, Daniele Vigano', Nanda Rea
The lack of X-ray pulsars with spin periods > 12 s raises the question about where the population of evolved high magnetic field neutron stars has gone. Unlike canonical radio-pulsars, X-ray pulsars are not subject to physical limits to the emission mechanism nor observational biases against the detection of sources with longer periods. Here we show that a highly resistive layer in the innermost part of the crust of neutron stars naturally limits the spin period to a maximum value of about 10-20 s. This high resistivity is one of the expected properties of the nuclear pasta phase, a proposed state of matter having nucleons arranged in a variety of complex shapes. Our findings suggest that the maximum period of isolated X-ray pulsars can be the first observational evidence of the existence of such phase, which properties can be constrained by future X-ray timing missions combined with more detailed models.
View original: http://arxiv.org/abs/1304.6546

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