Equations for the analysis of the light curves of extra-solar planetary transits
Equations for the analysis of the light curves of extra-solar planetary transits
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太阳系外行星凌日光变曲线分析方程
DOI：
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发表时间：
2006
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通讯作者：
Á. Giménez
中科院分区：
文献类型：
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作者：
Á. Giménez
本文提出了计算日外行星凌日光变曲线的简便解析公式。这些方程是行星和母星星的半径分数、轨道倾角和星星边缘变暗系数的函数。光变曲线可以根据可用观测的精度来求解这些参数。当径向速度曲线也可用时，通常情况下，为了确保系统的性质，星星和行星的质量，半径和平均密度都可以确定。这些方程对任何程度的临边暗化和任何类型的凌日都是有效的。偏心轨道、第三光或行星相对光度非零的情况都可以很容易地考虑进去。基本的假设是，星星和行星在天空平面上的投影可以用圆盘很好地表示。在这种假设是无效的情况下的影响进行了讨论。实际应用显示，开始与光度发现的行星OGLE-TR-113，获得了地面望远镜的光变曲线。作为第二个例子，结果显示从研究的光变曲线获得的过境的巨行星在HD 209458与哈勃太空望远镜。简要讨论了获得最佳拟合参数的步骤。
Easy to use analytical formulae are presented for the computation the of light curves of extra-solar planetary transits. The equations are a function of the fractional radii of the planet and the parent star, the inclination of the orbit, and the limb-darkening coefficients of the star. Light curves can be solved for these parameters depending on the precision of the available observations. When the radial velocity curve is also available, as is normally the case to ensure the nature of the system, the masses, radii, and average density of both the star and the planet can be determined. The equations are valid for any degree of limb darkening, as well as for any type of transit. The cases of eccentric orbits, third light, or a non-zero relative luminosity of the planet can be easily taken into account. The basic assumption is that the projections of both the star and the planet on the plane of the sky are well represented by circular discs. The effects in case this assumption is not valid are also discussed. Practical applications are shown, beginning with the light curve of the photometrically discovered planet OGLE-TR-113, obtained with a ground-based telescope. As a second example, results are shown from the study of the light curve obtained for the transit of the giant planet in HD 209458 with the Hubble Space Telescope . Procedures to get the best fit parameters are briefly discussed.