arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1702.05078astro-ph.EPastro-ph.SR
收藏

WASP-107上的星点和WASP-118的脉动

Starspots on WASP-107 and pulsations of WASP-118

T. Močnik, C. Hellier, D. R. Anderson, B. J. M. Clark, J. Southworth

摘要:

通过分析K2的短节奏测光,我们发现星点掩星事件的WASP-107,一个温暖的土星系外行星的宿主恒星的光变曲线。WASP-107还显示出旋转调制,周期为17.5 +/- 1.4 d。由于自转周期几乎是行星轨道周期的三倍,人们可以预期在一个排列整齐的系统中,每三次凌日就会发生一次星点掩星事件。如果没有这种掩星现象,就意味着轨道没有对准,除非恒星黑子的寿命短于恒星的自转周期。我们还发现恒星的变化类似于伽马剑鱼座脉动的WASP-118的光变曲线,它拥有一个膨胀的热木星。的可变性是多周期的可变半振幅约为200 ppm。除了这些发现之外,我们还使用K2数据来改进这两个系统的参数,并报告未检测到过境时间变化,次日食和任何其他过境行星。我们使用二次日食深度的上限来估计WASP-107 b和WASP-118 b的行星几何距离上限分别为0.7和0.2。

英文摘要:

By analysing the K2 short-cadence photometry we detect starspot occultation events in the lightcurve of WASP-107, the host star of a warm-Saturn exoplanet. WASP-107 also shows a rotational modulation with a period of 17.5 +/- 1.4 d. Given that the rotational period is nearly three times the planet's orbital period, one would expect in an aligned system to see starspot occultation events to recur every three transits. The absence of such occultation recurrences suggests a misaligned orbit unless the starspots' lifetimes are shorter than the star's rotational period. We also find stellar variability resembling gamma Doradus pulsations in the lightcurve of WASP-118, which hosts an inflated hot Jupiter. The variability is multi-periodic with a variable semi-amplitude of about 200 ppm. In addition to these findings we use the K2 data to refine the parameters of both systems, and report non-detections of transit-timing variations, secondary eclipses and any additional transiting planets. We used the upper limits on the secondary-eclipse depths to estimate upper limits on the planetary geometric albedos of 0.7 for WASP-107b and 0.2 for WASP-118b.

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。

↑