论文标题
SAX J1808.4-3658的二进制演变：进化供体星的含义
The binary evolution of SAX J1808.4-3658: Implications of an evolved donor star
论文作者
论文摘要
积聚动力的毫秒的脉冲星SAX J1808.4-3658的观察结果显示了一个有趣的二元演化，系统的轨道以加速速率扩展。我们使用了最近的发现，即SAX J1808.4-3658中的积聚燃料被氢化为大量优化祖细胞的模型和二元系统的先前演变。我们将同伴星的初始质量限制为1.0-1.2 m $ _ {\ mathrm {\ odot}} $，比该系统的先前进化研究更大。我们还推断该系统必须经历强烈的非保守传质，以解释观察到的轨道周期变化。在JIA＆LI（2015）之后，我们包括由于供体恒星的脉冲星辐射压力引起的质量损失，引起了在二进制系统内部拉格朗日点弹出的蒸发风。随之而来的角动量的额外损失可以解决保守的传质模型与观察到的轨道周期衍生物之间的差异。我们还包括由于积聚亮度而导致的供体照射的处理，并发现这对系统的演变具有不可忽略的影响。
Observations of the accretion powered millisecond pulsar SAX J1808.4-3658 have revealed an interesting binary evolution, with the orbit of the system expanding at an accelerated rate. We use the recent finding that the accreted fuel in SAX J1808.4-3658 is hydrogen depleted to greatly refine models of the progenitor and prior evolution of the binary system. We constrain the initial mass of the companion star to 1.0-1.2 M$_{\mathrm{\odot}}$, more massive than previous evolutionary studies of this system have assumed. We also infer the system must have undergone strongly non-conservative mass transfer in order to explain the observed orbital period changes. Following Jia & Li (2015), we include mass loss due to the pulsar radiation pressure on the donor star, inducing an evaporative wind which is ejected at the inner Lagrangian point of the binary system. The resulting additional loss of angular momentum resolves the discrepancy between conservative mass transfer models and the observed orbital period derivative of this system. We also include a treatment of donor irradiation due to the accretion luminosity, and find this has a non-negligible effect on the evolution of the system.
