Measuring Stellar Limb Darkening by Gravitational Microlensing
Measuring Stellar Limb Darkening by Gravitational Microlensing
复制标题
通过引力微透镜测量恒星边缘变暗
DOI：
10.1086/376787
复制
发表时间：
2003
期刊：
影响因子：
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通讯作者：
D. Heyrovský
中科院分区：
文献类型：
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作者：
D. Heyrovský
微透镜凌日事件的观测可以用来测量透镜星星的临边暗化。讨论了几种微透镜光变曲线反演方法的优缺点。在这项工作中选择的方法是反演通过分解的恒星表面亮度轮廓。我们构造了一个理想的基础，通过主成分分析的亮度轮廓模式大气计算。使用这样的基础的边缘暗化近似是上级那些使用标准的幂律边缘暗化法律。我们进行了全面的分析，包括详细的误差分析的方法模拟单透镜微透镜过境事件。在实际的低影响参数的事件中，可以恢复源的亮度轮廓，从源盘的中心到盘半径的0.9的相对精度为2%。我们表明，在特定的情况下，观察到的CNOO警报95-30事件的透镜红巨星的内在复杂的可变性阻碍了努力恢复其表面特征。
Observations of microlensing transit events can be used to measure the limb darkening of the lensed star. We discuss the advantages and drawbacks of several microlensing light-curve inversion methods. The method of choice in this work is inversion by means of decomposition of the stellar surface brightness profile. We construct an ideal basis by principal component analysis of brightness profiles obtained from model atmosphere calculations. Limb-darkening approximations using such a basis are superior to those using standard power-law limb-darkening laws. We perform a full analysis of simulated single-lens microlensing transit events including a detailed error analysis of the method. In realistic events with a low impact parameter the brightness profile of the source can be recovered with a relative accuracy of 2% from the center of the source disk to 0.9 of the disk radius. We show that in the particular case of the observed MACHO Alert 95-30 event the intrinsic complex variability of the lensed red giant hinders efforts to recover its surface features.