An analysis of the CoRoT-2 system: A young spotted star and its inflated giant planet
An analysis of the CoRoT-2 system: A young spotted star and its inflated giant planet
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CoRoT-2 系统分析：一颗年轻的斑点恒星及其膨胀的巨行星
DOI：
10.1051/0004-6361/201015051
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
M. Havel
中科院分区：
文献类型：
--
作者：
T. Guillot;M. Havel
CoRoT-2b是已知最大的系外行星之一。考虑到它的巨大质量，它的大半径无法用标准的演化模型来解释。有趣的是，这颗行星的母星星是一颗活跃的、快速旋转的类太阳星星，有很大一部分（7%到20%）的斑点。目的：我们希望提供对恒星-行星系统性质的限制，并了解行星的推断大尺寸是否可能是由于推断参数的系统误差，如果不是，如何解释。研究方法：我们结合联合收割机恒星和行星演化代码的基础上，所有可用的光谱和光度数据，以获得自洽的系统参数的约束。结果如下：我们没有发现恒星模型（包括斑点和恒星活动）的系统误差，这将产生所需的约10%的大小减少的星星，从而行星。发现了两类解：通常的主序解为该星星的行星质量为3.67+/-0.13 Mjup，半径为1.55+/-0.03 Rjup，年龄至少为130 Ma，考虑到该星星的快速自转和显著的活动，应该小于500 Ma。我们在前主序上确定了另一类解，在这种情况下，行星的质量是3.45\pm 0.27 Mjup，半径是1.50+/-0.06 Rjup，年龄在30到40 Ma之间。这些非常年轻的解为行星的大小提供了最简单的解释，然后可以通过从最初的热膨胀状态简单收缩来匹配，只要大气不透明度比通常假设的太阳组成大气增加约3倍。其他的解决方案意味着，在任何情况下，CoRoT-2b目前膨胀的半径是短暂的，并且是在不到20 Ma前发生的事件的结果：与另一颗100亿质量的行星的巨大撞击，或者与系统中另一个物体的相互作用，导致离心率显著上升，随后其轨道迅速圆化。结论：对CoRoT-2的其他观测可以帮助理解这个系统，包括搜索红外过量和碎片盘的存在以及搜索其他同伴。确定一个完整的红外光曲线，包括主凌日和次凌日，对于限制行星的大气特性和确定行星与星星的半径比，以减少由于恒星活动而产生的系统误差，也是非常有价值的。
Context: CoRoT-2b is one of the most anomalously large exoplanet known. Given its large mass, its large radius cannot be explained by standard evolution models. Interestingly, the planet's parent star is an active, rapidly rotating solar-like star with a large fraction (7 to 20%) of spots. Aims: We want to provide constraints on the properties of the star-planet system and understand whether the planet's inferred large size may be due to a systematic error on the inferred parameters, and if not, how it may be explained. Methods: We combine stellar and planetary evolution codes based on all available spectroscopic and photometric data to obtain self-consistent constraints on the system parameters. Results: We find no systematic error in the stellar modeling (including spots and stellar activity) that would yield the required ~10% reduction in size for the star and thus the planet. Two classes of solutions are found: the usual main sequence solution for the star yields for the planet a mass of 3.67+/-0.13 Mjup, a radius of 1.55+/-0.03 Rjup for an age that is at least 130Ma, and should be less than 500Ma given the star's fast rotation and significant activity. We identify another class of solutions on the pre-main sequence, in which case the planet's mass is 3.45\pm 0.27 Mjup, its radius is 1.50+/-0.06 Rjup for an age between 30 and 40 Ma. These extremely young solutions provide the simplest explanation for the planet's size which can then be matched by a simple contraction from an initially hot, expanded state, provided the atmospheric opacities are increased by a factor ~3 compared to usual assumptions for solar compositions atmospheres. Other solutions imply in any case that the present inflated radius of CoRoT-2b is transient and the result of an event that occurred less than 20 Ma ago: a giant impact with another Jupiter-mass planet, or interactions with another object in the system which caused a significant rise of the eccentricity followed by the rapid circularization of its orbit. Conclusions: Additional observations of CoRoT-2 that could help understanding this system include searches for infrared excess and the presence of a debris disk and searches for additional companions. The determination of a complete infrared lightcurve including both the primary and secondary transits would also be extremely valuable to constrain the planet's atmospheric properties and to determine the planet-to-star radius ratio in a manner less vulnerable to systematic errors due to stellar activity.
DOI：
10.1111/j.1365-2966.2009.14694.x
发表时间：
2009
影响因子：
4.8
作者：
Barker A
通讯作者：
Barker A
影响因子：
6.5
作者：
S. Czesla;K. Huber;U. Wolter;S. Schröter;J. Schmitt
通讯作者：
S. Czesla;K. Huber;U. Wolter;S. Schröter;J. Schmitt
CoRoT-2a 的行星食测绘 - 演化、差分自转和点偏移
影响因子：
6.5
作者：
Czesla;Wolter;Schmitt;J. H. M. M.
通讯作者：
J. H. M. M.