Deconvolving the HD 81809 Binary: Rotational and Activity Evidence for a Subgiant with a Sun-like Cycle
Deconvolving the HD 81809 Binary: Rotational and Activity Evidence for a Subgiant with a Sun-like Cycle
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对 HD 81809 二进制进行反卷积：具有类太阳周期的亚巨星的旋转和活动证据
DOI：
10.3847/1538-4357/aadf86
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
R. Egeland
中科院分区：
文献类型：
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作者：
R. Egeland
HD 81809是卫奕信天文台香港计划所观测到的恒星样本中质量最高的活动周期之一。然而，这个物体实际上是一个双星系统，它提出了一个问题，即哪个组分负责观察到的循环活动，以及该活性组分的性质是什么。Hipparcos航天器获得了该系统的分辨率双色光度，表明这两个成分都在太阳温度附近。结合精确的Gaia视差和经验测辐射热校正值，我们得到了和的亮度、半径和的分量，证实了主分量是一个亚巨星。我们对A分量的自转周期进行了独立估计，发现它与之前从CaHK时间序列测量的40.2天周期一致。我们探索了去卷积的S指数的合理情景，发现循环A分量的活动水平将在系综活动-旋转趋势的范围内，而循环B分量可能没有。根据已有的旋转和活度证据，我们发现该体系最有可能的特征是一个亚巨型主组分负责在CaHK中的平稳循环行为，而次要组分在处具有相对平坦的活性。
HD 81809 has one of the highest quality activity cycles from the sample of stars synoptically observed in the Mount Wilson Observatory HK Project. However, this object is in fact a binary system, raising the question as to which of the components is responsible for the observed cyclic activity and what are the properties of that active component. The Hipparcos spacecraft obtained resolved two-color photometry for this system that indicates that both components are near the solar temperature. Combined with the precise Gaia parallax and empirical bolometric corrections we derive component the luminosities of and , and radii and , confirming that the primary component is a subgiant. We perform an independent estimate of the rotation period of the A component based on and find that it agrees with the 40.2 days period previously measured from the Ca HK time series. We explore plausible scenarios for the deconvolved S-index and find that a cycling A component would have an activity level within the bounds of ensemble activity-rotation trends, while a cycling B component likely does not. Based on the available rotation and activity evidence, we find the most likely characterization of the system is a subgiant primary component responsible for the smooth cyclic behavior in Ca HK with , while the secondary component has relatively flat activity at .
2020 年 SOAR 散斑干涉测量
DOI：
10.3847/1538-3881/ac00bd
发表时间：
2021
期刊：
The Astronomical Journal
影响因子：
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作者：
Tokovinin, Andrei;Mason, Brian D.;Mendez, Rene A.;Costa, Edgardo;Mann, Andrew W.;Henry, Todd J.
通讯作者：
Henry, Todd J.