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arXiv 0901.4618astro-ph.SRastro-ph.EP
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光球活动和行星宿主星CoRoT-Exo-4a的旋转

Photospheric activity and rotation of the planet-hosting star CoRoT-Exo-4a

A. F. Lanza, S. Aigrain, S. Messina, G. Leto, I. Pagano, M. Auvergne, A. Baglin, P. Barge, A. S. Bonomo, A. Collier Cameron, G. Cutispoto, M. Deleuil, J. R. De … 展开作者

A. F. Lanza, S. Aigrain, S. Messina, G. Leto, I. Pagano, M. Auvergne, A. Baglin, P. Barge, A. S. Bonomo, A. Collier Cameron, G. Cutispoto, M. Deleuil, J. R. De Medeiros, B. Foing, C. Moutou

摘要:

空间实验CoRoT最近探测到一颗在中等活跃的F型主序星(CoRoT-Exo-4a)周围轨道上的凌日热木星。这个行星系统特别令人感兴趣,因为它的轨道周期为9.202天,是迄今为止已知的凌日行星中第二长的。我们研究的表面旋转和活动的宿主恒星在一个不间断的光学观测序列的58天。我们的方法是基于最大熵点建模技术广泛测试的太阳总辐照度的变化建模。它假设恒星活动区由冷斑和亮光斑组成,类似于太阳黑子和太阳光球光斑,其可见度受恒星自转的调制。CoRoT-Exo-4a的光变曲线模型揭示了三个主要的活跃天体,其寿命在30至60天之间,与行星的轨道运动准同步旋转。不同的旋转速率的活动的岩石圈解释的表面差异旋转和下限为0.057 \pm 0.015推导出其相对振幅。在靠近亚行星际经度的地方观测到的活动增强表明了一种磁性恒星-行星相互作用,尽管时间序列的持续时间很短,使我们无法得出明确的结论。

英文摘要:

The space experiment CoRoT has recently detected a transiting hot Jupiter in orbit around a moderately active F-type main-sequence star (CoRoT-Exo-4a). This planetary system is of particular interest because it has an orbital period of 9.202 days, the second longest one among the transiting planets known to date. We study the surface rotation and the activity of the host star during an uninterrupted sequence of optical observations of 58 days. Our approach is based on a maximum entropy spot modelling technique extensively tested by modelling the variation of the total solar irradiance. It assumes that stellar active regions consist of cool spots and bright faculae, analogous to sunspots and solar photospheric faculae, whose visibility is modulated by stellar rotation. The modelling of the light curve of CoRoT-Exo-4a reveals three main active longitudes with lifetimes between about 30 and 60 days that rotate quasi-synchronously with the orbital motion of the planet. The different rotation rates of the active longitudes are interpreted in terms of surface differential rotation and a lower limit of 0.057 \pm 0.015 is derived for its relative amplitude. The enhancement of activity observed close to the subplanetary longitude suggests a magnetic star-planet interaction, although the short duration of the time series prevents us from drawing definite conclusions.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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