TIC 366240660——一个外轨道周期极短（30.5天）的动态活跃三合星系统
TIC 366240660 - A Dynamically Active Triple With a Very Short Outer Period of 30.5 Days
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中文总结 AI 辅助
该研究分析TIC 366240660这一外周期仅30.5天的致密三合星系统，通过光动力学方法精确测定恒星参数，并发现其异常食变时与13:1平运动共振相关。
中文摘要 AI 辅助
方法：我们利用光动力学代码分析了三合星系统TIC 366240660的TESS测光数据、视向速度测量值和食变时（ETV）曲线，以推断三颗恒星的性质及轨道运动。结果：其外轨道周期仅为30.5天，是文献中报道的第二致密的三合星系统。我们确定了三颗恒星的质量和有效温度（$T_{\rm eff}$），精度约为1%，半径精度约为2%。两个轨道平面的倾角及相互倾角的精度优于1/3°。该系统被确定为相当平坦（倾角差在1/2°以内），但外轨道偏心率$e_{\rm out} \simeq 0.33$。我们发现内双星中次星的性质与孤立单星演化完全不符，它必定在先前的一次质量转移事件中将其大部分包层转移给了当前内双星的主星。由TESS测光数据导出的食变时（ETV）曲线显示，除了外轨道周期处典型的动力学延迟曲线外，还存在一个周期为840天、振幅大得多的异常正弦状延迟。ETV曲线中的这一特征目前尚无法用简单的解析项描述，但几乎可以肯定，它可以通过外轨道与内轨道周期之比接近整数（$\simeq$13:1）来解释。结论：我们广泛探索了这个高度致密三合星系统的奇异和异常的ETV，发现它们对于内双星食可超过数小时，对于外轨道食可达数天。我们初步解释了这些现象与外轨道和内轨道13:1平运动共振的关系。
英文摘要
Methods: We analyze TESS photometric data, radial velocity measurements, and eclipse timing variation curves for the triple star system, TIC 366240660, with a photodynamical code to infer the properties of all three stars and orbital motions. Results: With an outer orbital period of only 30.5 d, this is the second most compact triple reported in the literature. We have determined the masses and $T_{\rm eff}$ values of the three stars with an accuracy of about 1% and the radii to about 2%. The inclination angles of the two planes, and the mutual inclination angle are found with an accuracy of better than 1/3$^\circ$. The system is determined to be quite flat (to within 1/2$^\circ$), but with an outer eccentricity of $e_{\rm out} \simeq 0.33$. We find that the properties of the secondary star of the inner binary are completely inconsistent with the evolution of a single star in isolation, and it must have transferred most of its envelope to the current primary star in the inner binary during a prior episode of mass transfer. The eclipse timing variation (ETV) curve derived from the TESS photometric data shows that, in addition to a typical dynamical delay curve at the period of the outer orbit, there is also a much larger amplitude anomalous sinusoidal-like delay with a period of 840 d. This latter feature in the ETV curve is not yet describable in simple analytic terms, but it appears certain that it can be explained by the near integer ($\simeq$13:1) ratio of the outer to the inner orbital periods. Conclusions: We have extensively explored the exotic and anomalous ETVs of this highly compact triple system and found that they can exceed hours for the inner binary eclipses, and several days for the outer orbital eclipses. We provide a preliminary explanation for how these are related to the 13:1 mean motion resonance of the outer to inner orbits.
发表机构
- HUN–REN–SZTE Stellar Astrophysics Research Group（匈牙利科学院-塞格德大学恒星天体物理学研究组）
- Department of Physics, Kavli Institute for Astrophysics and Space Research, M.I.T.（麻省理工学院物理系卡弗里天体物理学与空间研究研究所）
- Baja Astronomical Observatory of University of Szeged（塞格德大学巴亚天文台）
- Konkoly Observatory, Research Centre for Astronomy and Earth Sciences（孔科利天文台，地球科学研究中心）
- Center for Astrophysics, Harvard & Smithsonian（哈佛-史密森尼天体物理中心）
- International Centre of Supernovae (ICESUN), Yunnan Key Laboratory of Supernova Research, Yunnan Observatories, Chinese Academy of Sciences (CAS)（中国科学院云南天文台超新星国际研究中心（ICESUN）云南省超新星研究重点实验室）
- Astronomical Institute, Faculty of Mathematics and Physics, Charles University（查理大学数学与物理学院天文研究所）
- FZU - Institute of Physics of the Czech Academy of Sciences（捷克科学院物理研究所）
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