HD 98800四重前主序列系统。利用长基线红外干涉测量法进行全面的轨道定性
The HD 98800 quadruple pre-main sequence system. Towards full orbital characterisation using long-baseline infrared interferometry
摘要：
HD 98800是一个年轻的（$\sim10$ Myr old）和附近的（$\sim45$ pc）四重星系，由两个光谱双星（AaAb和BaBb）组成，在BaBb周围有一个富含气体的盘，呈极配置。虽然BaBb和AB的轨道参数相对较好地受到约束，但AaAb的情况并非如此。对这一四重系统的全面描述可以为理解这样一个复杂系统的形成提供依据。这项工作的目标是确定AaAb子系统的轨道和完善的轨道解的BaBb使用多历元干涉观测VLTI/PIONIER和径向速度。PIONIER观测提供了AaAa和BaBb子系统的相对天体测量位置和通量比。结合天体测量点和径向速度测量，我们确定了两个子系统的轨道参数。我们改进了BaBb的轨道解，并首次导出了AaAb的全轨道解。我们证实了围绕BaBb的环双星盘的极位。从我们的解中，我们还推出了AaAb（$M_{Aa} = 0.93 \pm 0.09$和$M_{Ab} = 0.29 \pm 0.02$ M $_{\odot}$）的动力学质量.我们还重新讨论了AB外轨道的参数。使用N体模拟，我们表明，该系统应该是动态稳定的数千个轨道周期，它作出了初步预测的磁盘过境AaAb的前面，估计开始于2026年左右。我们讨论了AaAb周围缺乏磁盘，这可以解释为较大的X射线光度的AaAb，促进更快的光蒸发的磁盘。高分辨率红外光谱观测将提供Aa和Ab的径向速度（当代观测中的混合线），这将使我们能够独立于BaBb的视差计算Aa和Ab的动力学质量。
英文摘要：
HD 98800 is a young ($\sim10$ Myr old) and nearby ($\sim45$ pc) quadruple system, composed of two spectroscopic binaries orbiting around each other (AaAb and BaBb), with a gas-rich disk in polar configuration around BaBb. While the orbital parameters of BaBb and AB are relatively well constrained, this is not the case for AaAb. A full characterisation of this quadruple system can provide insights on the formation of such a complex system. The goal of this work is to determine the orbit of the AaAb subsystem and refine the orbital solution of BaBb using multi-epoch interferometric observations with the VLTI/PIONIER and radial velocities. The PIONIER observations provide relative astrometric positions and flux ratios for both AaAa and BaBb subsystems. Combining the astrometric points with radial velocity measurements, we determine the orbital parameters of both subsystems. We refined the orbital solution of BaBb and derived, for the first time, the full orbital solution of AaAb. We confirmed the polar configuration of the circumbinary disk around BaBb. From our solutions, we also inferred the dynamical masses of AaAb ($M_{Aa} = 0.93 \pm 0.09$ and $M_{Ab} = 0.29 \pm 0.02$ M$_{\odot}$). We also revisited the parameters of the AB outer orbit. Using the N-body simulation, we show that the system should be dynamically stable over thousands of orbital periods and that it made preliminary predictions for the transit of the disk in front of AaAb which is estimated to start around 2026. We discuss the lack of a disk around AaAb, which can be explained by the larger X-ray luminosity of AaAb, promoting faster photo-evaporation of the disk. High-resolution infrared spectroscopic observations would provide radial velocities of Aa and Ab (blended lines in contemporary observations), which would allow us to calculate the dynamical masses of Aa and Ab independently of the parallax of BaBb.
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