Testing the planetary models of HU Aquarii
Testing the planetary models of HU Aquarii
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DOI：
10.1093/mnras/stu1879
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发表时间：
2014-09
影响因子：
4.8
通讯作者：
M. Bours;T. Marsh;E. Breedt;C. Copperwheat;V. Dhillon;A. Leckngam;S. Littlefair;S. Parsons;A. Prasit
中科院分区：
文献类型：
--
作者：
M. Bours;T. Marsh;E. Breedt;C. Copperwheat;V. Dhillon;A. Leckngam;S. Littlefair;S. Parsons;A. Prasit
我们提出了极地（即半分离磁白矮星 + M 矮星双星）HU Aqr 的新日食观测结果，以及每次日食的中出时间，这些观测结果的观测时间越来越早。最近的日食发生时间比最新模型的预测早了 70 多秒，该模型利用单个环双星行星来解释观测到的轨道周期变化，从而最终证明该模型是不正确的。使用 ULTRACAM 数据，我们表明针对不同波长采集的同步数据确定的中出射时间彼此一致。由于数据拟合不佳以及短时间尺度上的轨道不稳定，观测到的日食时间的巨大变化无法用最多包含三颗行星的行星模型来解释。近 140 秒的 O−C 图峰峰值幅度也太大，不可能是由阿普尔盖特机制、白矮星表面吸积点的移动或白矮星的异步旋转引起的。是什么导致了观测到的日食时间变化仍然是个谜。
We present new eclipse observations of the polar (i.e. semidetached magnetic white dwarf + M-dwarf binary) HU Aqr, and mid-egress times for each eclipse, which continue to be observed increasingly early. Recent eclipses occurred more than 70 s earlier than the prediction from the latest model that invoked a single circumbinary planet to explain the observed orbital period variations, thereby conclusively proving this model to be incorrect. Using ULTRACAM data, we show that mid-egress times determined for simultaneous data taken at different wavelengths agree with each other. The large variations in the observed eclipse times cannot be explained by planetary models containing up to three planets, because of poor fits to the data as well as orbital instability on short time-scales. The peak-to-peak amplitude of the O−C diagram of almost 140 s is also too great to be caused by Applegate's mechanism, movement of the accretion spot on the surface of the white dwarf, or by asynchronous rotation of the white dwarf. What does cause the observed eclipse time variations remains a mystery.