Transit mapping of a starspot on CoRoT-2. Probing a stellar surface with planetary transits
Transit mapping of a starspot on CoRoT-2. Probing a stellar surface with planetary transits
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DOI：
10.1051/0004-6361/200912329
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发表时间：
2009-06
影响因子：
6.5
通讯作者：
U. Wolter;J. H. M. M. Schmitt-J.-H.-M.-M.-Schmitt-2244209165;K. Huber;S. Czesla;Hans Muller;E. Guenther;A. Hatzes
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文献类型：
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作者：
U. Wolter;J. H. M. M. Schmitt-J.-H.-M.-M.-Schmitt-2244209165;K. Huber;S. Czesla;Hans Muller;E. Guenther;A. Hatzes
我们分析了CoRoT-2b的凌日光曲线变化，CoRoT-2b是一颗围绕一颗高度活跃的G星运行的大质量热木星。我们用一条凌日光曲线来绘制一个被行星遮挡的光球点的日食图。在这个案例研究中，我们确定了星黑子掩食部分的大小和经度，并系统地研究了相应的不确定性。我们确定了恒星表面的光斑半径在4.5°到10.5°之间，光斑经度精度约为±1度。考虑到CoRoT-2系统众所周知的凌日几何形状，这意味着在通常被太阳黑子覆盖的纬度上可以可靠地探测到黑子；模型黑子的大小与太阳上的大型黑子群相当。我们讨论了通过行星凌日来绘制日食地图的未来潜力，以便对恒星表面特征进行高分辨率分析。
We analyze variations in the transit lightcurves of CoRoT-2b, a massive hot Jupiter orbiting a highly active G star. We use one transit lightcurve to eclipse-map a photospheric spot occulted by the planet. In this case study we determine the size and longitude of the eclipsed portion of the starspot and systematically study the corresponding uncertainties. We determine a spot radius between 4.5° and 10.5° on the stellar surface and the spot longitude with a precision of about ±1 degree. Given the well-known transit geometry of the CoRoT-2 system, this implies a reliable detection of spots on latitudes typically covered by sunspots; the size of the modelled spot is comparable to large spot groups on the Sun. We discuss the future potential of eclipse mapping by planetary transits for the high-resolution analysis of stellar surface features.