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arXiv 1406.2620astro-ph.SR
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没有来自WASP-18的X线片。它的年龄,活动及其巨大的热木星的影响

No X-rays from WASP-18. Implications for its age, activity, and the influence of its massive hot Jupiter

Ignazio Pillitteri, Scott J. Wolk, Salvatore Sciortino, Victoria Antoci

摘要:

在$>1000$已知的系外行星中,大约有20%是类似木星的行星,它们的轨道非常靠近它们的母恒星。目前仍在争论的是,这种热彗星可能通过潮汐或磁恒星-行星相互作用影响宿主恒星的活动。在本文中,我们报告了一个87 KS钱德拉观测热木星托管恒星WASP-18。该系统由一颗F6型恒星和一颗质量为$10.4 M_{Jup}$的热木星组成,木星围绕母星的公转周期小于20小时。根据等时线拟合,WASP-18的年龄被认为是6亿年,不确定性范围为0.5-2 Gyr。这颗恒星在X射线中的亮度极限为$4\times10^{26}$ erg/s,比这个年龄和质量的恒星低两个数量级以上。这个值证明了一颗估计年龄在6亿年左右的恒星不寻常的缺乏活动。我们认为,大质量的行星可以发挥至关重要的作用,扰乱恒星磁发电机内创建的薄对流层。在钱德拉图像中还探测到另外212个X射线源。我们列出它们并简要讨论它们的性质。

英文摘要:

About 20% out of the $>1000$ known exoplanets are Jupiter analogs orbiting very close to their parent stars. It is still under debate to what detectable level such hot Jupiters possibly affect the activity of the host stars through tidal or magnetic star-planet interaction. In this paper we report on an 87 ks Chandra observation of the hot Jupiter hosting star WASP-18. This system is composed of an F6 type star and a hot Jupiter of mass $10.4 M_{Jup}$ orbiting in less than 20 hr around the parent star. On the basis of an isochrone fitting, WASP-18 is thought to be 600 Myr old and within the range of uncertainty of 0.5-2 Gyr. The star is not detected in X-rays down to a luminosity limit of $4\times10^{26}$ erg/s, more than two orders of magnitude lower than expected for a star of this age and mass. This value proves an unusual lack of activity for a star with estimated age around 600 Myr. We argue that the massive planet can play a crucial role in disrupting the stellar magnetic dynamo created within its thin convective layers. Another additional 212 X-ray sources are detected in the Chandra image. We list them and briefly discuss their nature.

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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