How stellar activity affects the size estimates of extrasolar planets
How stellar activity affects the size estimates of extrasolar planets
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DOI：
10.1051/0004-6361/200912454
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发表时间：
2009-06
影响因子：
6.5
通讯作者：
S. Czesla;K. Huber;U. Wolter;S. Schröter;J. Schmitt
中科院分区：
文献类型：
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作者：
S. Czesla;K. Huber;U. Wolter;S. Schröter;J. Schmitt
光曲线长期以来一直用于研究恒星活动，最近成为系外行星研究领域的主要工具。我们讨论了恒星活动影响凌日光曲线的各种方式，并利用CoRoT-2系外行星系统的出色光度数据研究了这种影响。我们报告了“全球”光曲线和凌日曲线之间的关系，凌日曲线在恒星表面高光斑覆盖期间变浅。此外，我们的分析还揭示了凌日光曲线的颜色依赖性与在太阳上观测到的波长依赖性临边变暗规律相一致。考虑到与活动相关的影响，我们重新确定了轨道倾角和行星半径，发现行星比以前报道的大约3%。我们的发现还表明，系外行星研究通常不能忽视恒星活动的影响。
Light curves have long been used to study stellar activity and have more recently become a major tool in the field of exoplanet research. We discuss the various ways in which stellar activity can influence transit light curves, and study the effects using the outstanding photometric data of the CoRoT-2 exoplanet system. We report a relation between the “global” light curve and the transit profiles, which turn out to be shallower during high spot coverage on the stellar surface. Furthermore, our analysis reveals a color dependence of the transit light curve compatible with a wavelength-dependent limb darkening law as observed on the Sun. Taking into account activity-related effects, we redetermine the orbit inclination and planetary radius and find the planet to be ≈3% larger than reported previously. Our findings also show that exoplanet research cannot generally ignore the effects of stellar activity.