文章基本信息

标题：Glimpses of stellar surfaces - II. Origins of the photometric modulations and timing variations of KOI-1452
其他标题：II. Origins of the photometric modulations and timing variations of KOI-1452
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作者：P. Ioannidis ; P. Ioannidis ; J. H. M. M. Schmitt 等
期刊名称：Astronomy & Astrophysics
印刷版ISSN：0004-6361
电子版ISSN：1432-0746
出版年度：2016
卷号：594
页码：1-7
DOI：10.1051/0004-6361/201628295
语种：English
出版社：EDP Sciences
摘要：The deviations of the mid-transit times of an exoplanet from a linear ephemeris are usually the result of gravitational interactions with other bodies in the system. However, these types of transit timing variations (TTV) can also be introduced by the influences of star spots on the shape of the transit profile. Here we use the method of unsharp masking to investigate the photometric light curves of planets with ambiguous TTV to compare the features in their O−C diagram with the occurrence and in-transit positions of spot-crossing events. This method seems to be particularly useful for the examination of transit light curves with only small numbers of in-transit data points, i.e., the long cadence light curves from Kepler satellite. As a proof of concept we apply this method to the light curve and the estimated eclipse timing variations of the eclipsing binary KOI-1452, for which we prove their non-gravitational nature. Furthermore, we use the method to study the rotation properties of the primary star of the system KOI-1452 and show that the spots responsible for the timing variations rotate with different periods than the most prominent periods of the system’s light curve. We argue that the main contribution in the measured photometric variability of KOI-1452 originates in g-mode oscillations, which makes the primary star of the system a γ-Dor type variable candidate.
关键词：planetary systems;starspots;occultations;eclipses;stars: activity;methods: data analysis