文章基本信息

标题：Orbital Period Variation of KIC 10544976: Applegate Mechanism versus Light Travel Time Effect
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作者：L. A. Almeida ; L. de Almeida ; A. Damineli 等
期刊名称：The Astronomical journal
印刷版ISSN：0004-6256
电子版ISSN：1538-3881
出版年度：2019
卷号：157
期号：4
页码：1-7
DOI：10.3847/1538-3881/ab0963
语种：English
出版社：American Institute of Physics
摘要：In recent years, several close post-common-envelope eclipsing binaries have been found to show cyclic eclipse timing variations (ETVs). This effect is usually interpreted either as the gravitational interaction among circumbinary bodies and the host binary—known as the light travel time (LTT) effect—or as the quadrupole moment variations in one magnetic active component—known as the Applegate mechanism. In this study, we present an analysis of the ETV and the magnetic cycle of the close binary KIC 10544976. This system is composed of a white dwarf and a red dwarf in a short orbital period (0.35days) and was monitored by ground-based telescopes between 2005 and 2017 and by the Kepler satellite between 2009 and 2013. Using the Kepler data, we derived the magnetic cycle of the red dwarf by two ways: the rate and energy of flares and the variability due to spots. Both methods resulted in a cycle of ∼600days, which is in agreement with magnetic cycles measured for single low-mass stars. The orbital period of KIC 10544976 shows only one long-term variation which can be fitted by an LTT effect with period of ∼16.8yr. Hence, one possible explanation for the ETVs is the presence of a circumbinary body with a minimal mass of ∼13.4M Jup . In the particular scenario of coplanarity between the external body and the inner binary, the third body mass is also ∼13.4M Jup . In this case, the circumbinary planet must either have survived the evolution of the host binary or have been formed as a consequence of its evolution.
关键词：binaries: eclipsing;planetary systems;stars: activity;stars: flare;stars: individual (KIC 10544976);starspots