AI 中文总结
研究HD 98800四重系统中圆盘绕BaBb在AaAb前的掩星，通过结合新和已发表测量及多波长天体测量进行联合轨道拟合，更新轨道解，缩小预测窗口，为掩星观测提供更准计时框架，虽预测历元依赖模型。
AI 中文摘要
HD 98800是一个年轻的层级四重系统，由紧密双星AaAb和BaBb组成，处于宽阔、高度倾斜的外轨道。B子系统有一个极地构型的环绕双星圆盘，该系统的几何结构提供了一个罕见机会，可观测圆盘绕BaBb在AaAb前的通过情况。我们旨在通过将轨道与圆盘结构的最新知识相结合来更新整体轨道解，以提供主要掩星特征的精确时间窗口。我们在联合轨道拟合中结合了新的和已发表的径向速度测量以及外AB轨道和内子系统AaAb、BaBb的多波长天体测量。修订后的解与先前的动力学质量一致，改进了外轨道，将周期和近星点历元的不确定性降低了约一半。它还将预测的穿越阶段窗口在1σ水平上缩小到5 - 15天，改善了进、出和首次穿越空洞的计时预测。这些结果为未来掩星观测提供了更准确的计时框架，不过由于圆盘结构的不确定性，预测历元仍依赖模型。
英文摘要
HD 98800 is a young hierarchical quadruple system composed of the tight binaries AaAb and BaBb on a wide, highly inclined outer orbit. The B subsystem hosts a circumbinary disc in a polar configuration, and the geometry of the system offers a rare opportunity to observe the passage of the disc around BaBb in front of AaAb. We aim to update the overall orbital solution to offer precise time windows of the main occultation features by combining the orbit with the state-of-the-art knowledge of the disc's structure. We combine new and published radial-velocity measurements and multi-wavelength astrometry for the outer AB orbit and both inner subsystems, AaAb and BaBb, in a joint orbital fit. The revised solution is consistent with previous dynamical masses and improved the outer orbit, reducing the uncertainties in the period and periastron epoch by about a factor of two. It also narrows the predicted crossing-phase windows to 5--15 days at the 1σ level, improving the timing of ingress, egress, and the first cavity-crossing predictions. These results provide a more accurate timing framework for future observations of the occultation, although the predicted epochs remain model-dependent because of uncertainties in the disc structure.
CommentsAccepted A&A Letter to the Editor. 4 pages main text and 4 pages Appendix
