Rotating protoneutron stars: Spin evolution, maximum mass, and I-Love-Q relations
Rotating protoneutron stars: Spin evolution, maximum mass, and I-Love-Q relations
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旋转的中子星：自旋演化、最大质量和 I-Love-Q 关系
DOI：
10.1103/physrevd.90.064026
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发表时间：
2014
影响因子：
5
通讯作者：
V. Ferrari
中科院分区：
文献类型：
--
作者：
Gr'egoire Martinon;A. Maselli;L. Gualtieri;V. Ferrari
一颗原中子星星在引力坍缩中诞生后不久，就进入了一个准稳态演化阶段，其特征是巨大的热力学变量梯度和强烈的中微子发射。在几十秒内，当星星收缩并冷却下来时，梯度变得平滑，直到它成为中子星星。在本文中，我们研究了这一阶段的原中子星星的生活，包括旋转，并采用有限温度状态方程。我们模拟了自转速率的演化，并确定了表征星星的相关量。我们的结果表明，一个孤立的中子星星不能达到，在演化结束时，质量和旋转速率的最大值所允许的零温度状态方程。此外，一颗孤立演化的成熟中子星星，即使它是从一颗以质量脱落极限旋转的原中子星星中诞生的，也不能旋转得太快。我们还表明，I-Love-Q关系在生命的第一秒就被违反了，但是一旦熵梯度平滑，它们就被满足了。
Shortly after its birth in a gravitational collapse, a proto-neutron star enters in a phase of quasi-stationary evolution characterized by large gradients of the thermodynamical variables and intense neutrino emission. In few tens of seconds the gradients smooth out while the star contracts and cools down, until it becomes a neutron star. In this paper we study this phase of the proto-neutron star life including rotation, and employing finite temperature equations of state. We model the evolution of the rotation rate, and determine the relevant quantities characterizing the star. Our results show that an isolated neutron star cannot reach, at the end of the evolution, the maximum values of mass and rotation rate allowed by the zero-temperature equation of state. Moreover, a mature neutron star evolved in isolation cannot rotate too rapidly, even if it is born from a proto-neutron star rotating at the mass-shedding limit. We also show that the I-Love-Q relations are violated in the first second of life, but they are satisfied as soon as the entropy gradients smooth out.