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arXiv 1812.07155astro-ph.HE
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核反应速率不确定性对从X射线爆发模型中提取的中子星性质的影响-观测比较

Influence of Nuclear Reaction Rate Uncertainties on Neutron Star Properties Extracted From X-ray Burst Model-Observation Comparisons

Zach Meisel, Grant Merz, Sophia Medvid

摘要:

I型X射线爆发可以通过模型计算和天文观测之间的比较来确定吸积中子星的性质,利用模型对天体物理条件的敏感性。然而,模型对核物理不确定性的敏感性使得以这种方式导出的约束的保真度受到质疑。使用X射线暴模型计算与代码{ \tt MESA},我们调查的影响,不确定性的核反应率以前确定为有影响力的,并比较它们的影响,在天体物理条件的变化,使用的条件,被认为是最好的再现源GS 1826-24作为基线。我们发现,反应速率的不确定性是不可能显着改变的结论吸积到中子星表面的属性为这个源。然而,我们发现,反应速率的不确定性显着阻碍了提取中子星质量半径比的可能性,通过匹配建模和观察到的光变曲线,由于反应速率的影响建模的光变曲线的形状。特别有影响的核反应率是$^{15}{\rm O}(α,γ)$和$^{23}{\rm Al}(p,γ)$,尽管其他显著影响来自$^{14}{\rm O}(α,p)$、$^{18}{\rm Ne}(α,p)$、$^{22}{\rm Mg}(α,p)$、$^{24}{\rm Mg}(α,γ)$、$^{59}{\rm Cu}(p,γ)$和$^{61}{\rm Ga}(p,γ)$。此外,我们发现,改变一些核反应率在其不确定性的影响,中子星地壳的组成和热结构,是比较显着的变化吸积条件。

英文摘要:

Type-I X-ray bursts can be used to determine properties of accreting neutron stars via comparisons between model calculations and astronomical observations, exploiting the sensitivity of models to astrophysical conditions. However, the sensitivity of models to nuclear physics uncertainties calls into question the fidelity of constraints derived in this way. Using X-ray burst model calculations performed with the code {\tt MESA}, we investigate the impact of uncertainties for nuclear reaction rates previously identified as influential and compare them to the impact of changes in astrophysical conditions, using the conditions that are thought to best reproduce the source GS 1826-24 as a baseline. We find that reaction rate uncertainties are unlikely to significantly change conclusions about the properties of accretion onto the neutron star surface for this source. However, we find that reaction rate uncertainties significantly hinder the possibility of extracting the neutron star mass-radius ratio by matching the modeled and observed light curves due to the influence of reaction rates on the modeled light curve shape. Particularly influential nuclear reaction rates are $^{15}{\rm O}(α,γ)$ and $^{23}{\rm Al}(p,γ)$, though other notable impacts arise from $^{14}{\rm O}(α,p)$, $^{18}{\rm Ne}(α,p)$, $^{22}{\rm Mg}(α,p)$, $^{24}{\rm Mg}(α,γ)$, $^{59}{\rm Cu}(p,γ)$, and $^{61}{\rm Ga}(p,γ)$. Furthermore, we find that varying some nuclear reaction rates within their uncertainties has an impact on the neutron star crust composition and thermal structure that is comparable to relatively significant changes accretion conditions.

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