论文标题
热核（I型）爆发期间核燃烧的效率随吸积率的函数
The efficiency of nuclear burning during thermonuclear (Type I) bursts as a function of accretion rate
论文作者
论文摘要
我们测量了五个低质量X射线二进制系统的I型X射线爆发的增生速率的热核燃烧效率。我们从大型观察样本中选择了测得的中子星旋转和大量爆发的来源。对于所有来源，爆发率的总体趋势在质量上都是相同的。爆发率首先随着积聚率的最大增加而增加，尽管积聚率增加，但爆发率下降。在较高的积聚速率下，当爆发速率降低时，α值（增生能量和爆发能量的比率）在上升的爆发速率状态下的倍数高达10倍。这些观察结果与1D数值模型的预测背道而驰，但可以解释为中子恒星表面稳定燃烧区域的结果，中子恒星表面随着增生速率的增加而扩展。稳定的燃烧还可以“污染”不稳定的燃烧层，上面有灰烬，这有助于在下降爆发速率方面测得的爆发特性的变化。我们发现，爆发速率开始降低的质量吸积率与中子恒星的自旋抗相关。我们得出的结论是，中子恒星旋转是一个关键因素，可以通过恒星上的局部积聚速率和燃料组成来调节核燃烧稳定性。
We measured the thermonuclear burning efficiency as a function of accretion rate for the Type I X-ray bursts of five low-mass X-ray binary systems. We chose sources with measured neutron star spins and a substantial population of bursts from a large observational sample. The general trend for the burst rate is qualitatively the same for all sources; the burst rate first increases with the accretion rate up to a maximum, above which the burst rate declines, despite the increasing accretion rate. At higher accretion rates, when the burst rate decreases, the α-value (the ratio of accretion energy and burst energy) increases by up to a factor of 10 above that in the rising burst rate regime. These observations are contrary to the predictions of 1D numerical models, but can be explained as the consequence of a zone of stable burning on the neutron star surface, which expands with increasing accretion rate. The stable burning also "pollutes" the unstable burning layer with ashes, contributing to the change in burst properties measured in the falling burst rate regime. We find that the mass accretion rate at which the burst rate begins to decrease is anti-correlated with the spin of the neutron star. We conclude that the neutron star spin is a key factor, moderating the nuclear burning stability, via the local accretion rate and fuel composition over the star.
