The Rossiter-McLaughlin Effect and Analytic Radial Velocity Curves for Transiting Extrasolar Planetary Systems
The Rossiter-McLaughlin Effect and Analytic Radial Velocity Curves for Transiting Extrasolar Planetary Systems
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DOI：
10.1086/428344
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发表时间：
2004-10
期刊：
影响因子：
--
通讯作者：
Y. Ohta;A. Taruya;Y. Suto
中科院分区：
文献类型：
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作者：
Y. Ohta;A. Taruya;Y. Suto
一颗凌日的太阳系外行星以一种与时间相关的方式依次阻挡来自宿主星星盘面不同部分的光线。由于星星的自旋，这会在恒星光谱的线轮廓中产生不对称的扭曲，导致径向速度曲线中的明显异常，称为罗西特-麦克劳克林效应。在这里，我们推导出近似的，但准确的径向速度曲线的异常的解析公式，考虑到恒星的临边暗化。这些公式在提取行星轨道轴和恒星自转轴之间的投影角λ和投影恒星自转速度V sin Is的信息时特别有用。我们为凌日系HD 209458的径向曲线创建了模拟样本，并证明了通过将我们的分析模板公式与8-10 m级望远镜高分辨率光谱观测的精确速度曲线相结合，可以显着改善对自旋参数（V sin Is，λ）的约束。因此，未来利用罗西特-麦克劳克林效应对凌日系统进行观测探索，将是更好地了解太阳系外行星系统起源，特别是其角动量起源的最重要的探索之一。
A transiting extrasolar planet sequentially blocks off the light coming from the different parts of the disk of the host star in a time-dependent manner. Because of the spin of the star, this produces an asymmetric distortion in the line profiles of the stellar spectrum, leading to an apparent anomaly in the the radial velocity curves, known as the Rossiter-McLaughlin effect. Here, we derive approximate but accurate analytic formulae for the anomaly in the radial velocity curves, taking into account the stellar limb darkening. The formulae are particularly useful in extracting information on the projected angle between the planetary orbit axis and the stellar spin axis, λ, and the projected stellar spin velocity, V sin Is. We create mock samples for the radial curves for the transiting extrasolar system HD 209458 and demonstrate that constraints on the spin parameters (V sin Is, λ) can be significantly improved by combining our analytic template formulae and the precision velocity curves from high-resolution spectroscopic observations with 8-10 m class telescopes. Thus, future observational exploration of transiting systems using the Rossiter-McLaughlin effect will be one of the most important probes for a better understanding of the origin of extrasolar planetary systems, especially the origin of their angular momentum.