Cyclic Period Oscillation of the Eclipsing Dwarf Nova DV UMa
Cyclic Period Oscillation of the Eclipsing Dwarf Nova DV UMa
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DOI：
10.3847/1538-3881/aa6c2a
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发表时间：
2017-05
期刊：
影响因子：
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通讯作者：
Z.-T. Han;S. Qian;V. Irina;L.-Y. Zhu
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文献类型：
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作者：
Z.-T. Han;S. Qian;V. Irina;L.-Y. Zhu
DV UMa是一颗轨道周期约2.06小时的食矮星新星，正好位于周期间隙的底部边缘。为了检测它的轨道周期变化，我们利用CCD光度数据和档案数据，提出了12个新的日食中期时间。最新版本的O-C图，结合已公布的日食中期静止时间，跨度为30年，得到并分析了。最佳拟合这些可用的日食时间表明，DV UMa的轨道周期正在经历一个周期为年的周期振荡，振幅为s。周期变化很可能是由于存在环双星物体引起的光传播时间效应，因为在这个系统中驱动Applegate机制所需的能量太高了。看不见的伴星的质量推导为。如果第三个天体在食对的轨道平面上，这将表明它是一颗褐矮星。这颗假设的褐矮星在距离约8.6 au的偏心轨道（e = 0.44）上绕着它的主星运行。
DV UMa is an eclipsing dwarf nova with an orbital period of ∼2.06 hr, which lies just at the bottom edge of the period gap. To detect its orbital period changes, we present 12 new mid-eclipse times by using our CCD photometric data and archival data. The latest version of the O–C diagram, combined with the published mid-eclipse times in quiescence, and spanning ∼30 years, was obtained and analyzed. The best fit to those available eclipse timings shows that the orbital period of DV UMa is undergoing a cyclic oscillation with a period of years and an amplitude of s. The periodic variation most likely arises from the light-travel-time effect via the presence of a circumbinary object, because the required energy to drive the Applegate mechanism is too high in this system. The mass of the unseen companion was derived as . If the third body is in the orbital plane (i.e., ) of the eclipsing pair, this would indicate it is a brown dwarf. This hypothetical brown dwarf is orbiting its host star at a separation of ∼8.6 au in an eccentric orbit (e = 0.44).