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Multi-color photometry with SOFIA: Spots on the solar-like star CoRoT-2A and their effect on its exoplanet CoRoT-2b

SOFIA 的多色光度测定：类太阳恒星 CoRoT-2A 上的斑点及其对其系外行星 CoRoT-2b 的影响

基本信息

批准号：
239961424
负责人：
Dr. Klaus Felix Huber
金额：
--
依托单位：
Hamburger Sternwarte
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2013
资助国家：
德国
起止时间：
2012-12-31 至 2016-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/239961424?language=en
关键词：
Multi color photometry SOFIA Spots

项目摘要

My collaborators and I will observe one transit of the exoplanet CoRoT-2b in front of its very active host-star CoRoT-2A. For the first time we will be able to obtain quasi-space-based, short-cadence photometry in the optical and the near-infrared simultaneously for an uninterrupted time period of more than 3 hours. The SOFIA data will provide us with the information necessary to investigate two issues:(a) Are exoplanetary radii inflated?Current research shows that many Jupiter-like exoplanets have radii much larger than theoretical predictions. Using CoRoT data our group has already shown that the activity of the host-star causes systematic errors in the determination of planetary parameters, i.e., the planet radius. Our SOFIA observations will allow us to examine how much of the planet's inflated radius is caused by starspots on the stellar surface. The result will help us to understand whether the observed inflation really is due to an yet not understood physical process expanding the planet or some consequence of stellar activity affecting the lightcurves.(b) What are the physical properties of starspots?Lightcurves can be used to reconstruct dark spots on the surface of a star. For this task, transiting planets are of special interest: When the planet moves across the stellar disk, it scans the surface of the star and all brightness inhomogeneities are imprinted onto the profile of the transit. Our group has already used this method to reconstruct the surface evolution of CoRoT-2A over a time period of almost half a year using the data of the CoRoT satellite. The SOFIA observations will give us additional information in the near-infrared, which was not provided by CoRoT. For the first time, it will be possible to measure the temperature of spots on the surface of CoRoT-2A independent of the unknown size of the spots. If we are able to resolve the umbra and penumbra of an individual spot in our observations, it will also be possible to measure - for the very first time - the structure and umbra/penumbra temperatures of spots on another solar-like star.

我的合作者和我将观察一颗系外行星CoRoT-2b在其非常活跃的宿主恒星CoRoT-2A前面的凌日。这是第一次，我们将能够获得准空间为基础的，短节奏测光在光学和近红外同时为一个不间断的时间超过3小时。索菲亚的数据将为我们研究两个问题提供必要的信息：（a）系外行星半径是否膨胀？目前的研究表明，许多类太阳系外行星的半径比理论预测大得多。利用CoRoT数据，我们的研究小组已经表明，主星的活动会导致行星参数确定的系统误差，即，行星半径我们的索菲亚观测将使我们能够检查行星的膨胀半径有多少是由恒星表面的恒星黑子引起的。这一结果将帮助我们理解观测到的暴胀是否真的是由于一个尚未理解的物理过程使行星膨胀，或者是恒星活动影响光变曲线的结果。(b)恒星黑子的物理性质是什么？光变曲线可以用来重建星星表面的黑点。对于这项任务，凌日行星是特别感兴趣的：当行星穿过恒星盘时，它会扫描星星的表面，所有亮度的不均匀性都会印在凌日的轮廓上。我们的团队已经使用这种方法利用CoRoT卫星的数据重建了CoRoT-2A在近半年时间内的表面演变。索菲亚观测将为我们提供近红外的额外信息，这是CoRoT没有提供的。这是第一次，它将有可能测量的温度点上的表面CoRoT-2A独立的未知大小的斑点。如果我们能够在观测中分辨出单个光斑的本影和半影，那么也就有可能首次测量另一颗类太阳星星上光斑的结构和本影/半影温度。