Too much pasta for pulsars to spin down
Too much pasta for pulsars to spin down
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发表时间：
2013
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通讯作者：
J. Pons;D. Viganò;N. Rea
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作者：
J. Pons;D. Viganò;N. Rea
缺乏自旋周期> 12 s的X射线中子星提出了一个问题，即演化的高磁场中子星的种群去了哪里。与典型射电脉冲星不同，X射线脉冲星不受发射机制的物理限制，也不受对较长周期源检测的观测偏差的影响。在这里，我们表明，在中子星地壳的最里面的一个高电阻层自然限制自旋周期的最大值约为10-20秒。这种高电阻率是核面食相的预期特性之一，核面食相是一种具有以各种复杂形状排列的核子的物质状态。我们的研究结果表明，孤立X射线天体的最大周期可以是存在这种相位的第一个观测证据，其属性可以受到未来X射线计时任务与更详细模型相结合的限制。
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.