PREDICTING PHOTOMETRIC AND SPECTROSCOPIC SIGNATURES OF RINGS AROUND TRANSITING EXTRASOLAR PLANETS
PREDICTING PHOTOMETRIC AND SPECTROSCOPIC SIGNATURES OF RINGS AROUND TRANSITING EXTRASOLAR PLANETS
复制标题
预测凌日系外行星周围环的光度和光谱特征
DOI：
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发表时间：
2006
期刊：
影响因子：
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通讯作者：
Y. Suto
中科院分区：
文献类型：
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作者：
Y. Ohta;A. Taruya;Y. Suto
我们提出了对凌日系外行星周围环的光度和光谱特征的理论预测。基于恒星光变曲线中的凌日特征和罗西特效应引起的速度异常的一般公式，我们对面向环系统的预期信号进行了分析计算，并针对更一般的配置进行了数值计算。我们研究了位于 a = 3 AU 的凌日行星周围的环在各种倾角和方位角下的可检测性，并发现可以通过光度和光谱来检测环特征，除非环几乎是边缘在上（即环的倾角 θ 远小于 1）。我们还考虑了围绕近距离行星 HD 209458b（θ ≈ 90° − iorbit ≈ 3.°32）和土星（θ ≈ 26.°7）的行星环的可探测性作为说明性示例。虽然前者很难以当前精度（10−4 的光度精度和 1 m s−1 的径向速度精度）检测到，但后者可以通过光度检测进行边缘检测。如果未来径向速度测量的精度低于 0.1 m s−1，甚至可以通过地面光谱观测来检测到它们。
We present theoretical predictions for the photometric and spectroscopic signatures of rings around transiting extrasolar planets. On the basis of a general formulation for the transiting signature in the stellar light curve and the velocity anomaly due to the Rossiter effect, we compute the expected signals analytically for a face-on ring system, and numerically for more general configurations. We study the detectability of a ring around a transiting planet located at a = 3 AU for a variety of obliquity and azimuthal angles, and find that it is possible to detect the ring signature both photometrically and spectroscopically unless the ring is almost edge-on (i.e., the obliquity angle, θ, of the ring is much less than unity). We also consider the detectability of planetary rings around a close-in planet, HD 209458b (θ ≈ 90° − iorbit≈ 3.°32), and Saturn (θ ≈ 26.°7) as illustrative examples. While the former is difficult to detect with the current precision (photometric precision of 10−4 and radial velocity precision of 1 m s−1), a marginal detection of the latter is possible photometrically. If the future precision of the radial velocity measurement goes below 0.1 m s−1, they will even be detectable from ground-based spectroscopic observations.