Deformation of a magnetized neutron star
Deformation of a magnetized neutron star
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DOI：
10.1103/physrevc.89.045805
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发表时间：
2013-07
影响因子：
3.1
通讯作者：
R. Mallick;S. Schramm
中科院分区：
文献类型：
--
作者：
R. Mallick;S. Schramm
磁星是一种致密的恒星，在观测上被确定具有非常强的表面磁场，其数量级为10 ^{14}-10 15}$G。星星的中心可能有一个大几个数量级的磁场。我们研究磁场对这种星星的质量和形状的影响。一般来说，我们假设星星内部有一个随密度变化的非均匀磁场。磁能量和压力以及度规被展开为球谐多极子，直到四极项。求解引力势的爱因斯坦方程，可以得到作为磁场函数的修正项。利用强子EoS的非线性模型，当表面场为10 ^{15}$G，中心场约为10 ^{18}$ G时，磁场引起的星星多余质量和赤道半径变化是相当显著的。当中心磁场强度为1.75 × 10 ^{18} G时，我们发现星星的多余质量和赤道半径都比球解变化了3 - 4%.
Magnetars are compact stars which are observationally determined to have very strong surface magnetic fields of the order of $10^{14}-10^{15}$G. The centre of the star can potentially have a magnetic field several orders of magnitude larger. We study the effect of the field on the mass and shape of such a star. In general, we assume a non-uniform magnetic field inside the star which varies with density. The magnetic energy and pressure as well as the metric are expanded as multipoles in spherical harmonics up to the quadrupole term. Solving the Einstein equations for the gravitational potential, one obtains the correction terms as functions of the magnetic field. Using a nonlinear model for the hadronic EoS the excess mass and change in equatorial radius of the star due to the magnetic field are quite significant if the surface field is $10^{15}$G and the central field is about $10^{18}$ G. For a value of the central magnetic field strength of $1.75\times10^{18}$ G, we find that both the excess mass and the equatorial radius of the star changes by about $3-4\%$ compared to the spherical solution.