论文标题
分析光曲线，用于跨肢体恒星的两个物体相互转移
Analytic Light Curve for Mutual Transits of Two Bodies Across a Limb-darkened Star
论文作者
论文摘要
我们为两个物体的光曲线提供了一个解决方案，该物体与多项式肢体变暗的恒星相互传播。这项工作中的“相互过境”一词是指恒星的过境，在此期间，两个过境体之间发生重叠。这些可能是一个外观伴侣，两个系外行星，一个黯然失色的二进制和一个行星，或两颗恒星在三星级系统中黯然失色的恒星。我们将光曲线的分析衍生物相对于两个身体的位置和半径。我们提供了实现相互交通的光动力模型的代码。我们包括两个动态模型，一个用于层次系统，其中二级机构绕较大的主要原理（例如外观系统）旋转，而一个用于共焦系统的第二个机构，其中两个物体独立绕中央质量绕中心质量（例如，两个具有广泛分离的轨道的行星）。我们的代码足够快以启用MCMC算法的推断，并且包含衍生物允许使用基于梯度的推理方法，例如Hamiltonian Monte Carlo。虽然适用于各种系统，但这项工作主要是考虑到外来的。我们希望公开提供此守则将减少社区评估外事物的可检测性，进行外事物的搜索以及试图验证现有的外来候选人的障碍。我们还预计，我们的代码对于系外行星系统，环形行星的过渡和三星级系统中的日食的研究将很有用。
We present a solution for the light curve of two bodies mutually transiting a star with polynomial limb darkening. The term "mutual transit" in this work refers to a transit of the star during which overlap occurs between the two transiting bodies. These could be an exoplanet with an exomoon companion, two exoplanets, an eclipsing binary and a planet, or two stars eclipsing a third in a triple star system. We include analytic derivatives of the light curve with respect to the positions and radii of both bodies. We provide code that implements a photodynamical model for a mutual transit. We include two dynamical models, one for hierarchical systems in which a secondary body orbits a larger primary (e.g. an exomoon system) and a second for confocal systems in which two bodies independently orbit a central mass (e.g. two planets in widely separated orbits). Our code is fast enough to enable inference with MCMC algorithms, and the inclusion of derivatives allows for the use of gradient-based inference methods such as Hamiltonian Monte Carlo. While applicable to a variety of systems, this work was undertaken primarily with exomoons in mind. It is our hope that making this code publicly available will reduce barriers for the community to assess the detectability of exomoons, conduct searches for exomoons, and attempt to validate existing exomoon candidates. We also anticipate that our code will be useful for studies of planet-planet transits in exoplanetary systems, transits of circumbinary planets, and eclipses in triple-star systems.
