发表机构
University of Canterbury; University College Cork; University of Oxford（坎特伯雷大学; 科克大学学院; 牛津大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究通过化学分配模型与APOGEE恒星丰度数据，预测星际天体组成与母星金属丰度相关，氨丰度可作示踪物，并推断2I和3I的起源恒星金属丰度，为未来发现提供背景。
AI 中文摘要
作为遥远行星系统的物理样本，星际天体（ISO）的组成应与其多样化的母恒星性质相关。我们将化学分配模型与来自APOGEE DR17的恒星元素丰度样本相结合，以预测星际天体（ISO）中常见彗发挥发物的丰度。我们发现，不同恒星形成的星际天体（ISO）的组成差异显著。特别是，我们预测星际天体（ISO）的氨丰度与其母恒星的金属丰度之间存在强相关性：高金属丰度恒星将产生富含氨的星际天体（ISO）。这表明NH$_3$的光解子产物的产生速率是星际天体（ISO）起源的理想观测示踪物。我们推断，2I/Borisov形成于一颗接近太阳金属丰度（$-0.4\backsimeq[\text{Fe}/\text{H}]\backsimeq0.3$）的恒星周围，并证实了基于速度和同位素的推断，即3I/ATLAS形成于一颗较低金属丰度（$-0.8\backsimeq[\text{Fe}/\text{H}]\backsimeq0.0$）的恒星周围。2I和3I的产生速率表明，两者仅含有被其他挥发性较弱的冰所捕获的超挥发物，如CO和N$_2$，这与典型的太阳系彗星相似。尽管如此，我们认为真正富含超挥发性冰的星际天体（ISO）可能存在；它们可能表现出高CO和N$_2$产生速率比，可能类似于C/2016 R2（PanSTARRS）。我们的预测为未来星际天体（ISO）的发现提供了背景，开辟了将其起源系统的性质与可观测的产生速率联系起来的途径。
英文摘要
As physical samples of distant planetary systems, the compositions of interstellar objects (ISOs) should correlate with the properties of their diverse parent stars. We combine a chemical partition model with a sample of stellar elemental abundances from APOGEE DR17 to predict the abundances of commonly-observed cometary volatiles in ISOs. We find that the compositions of ISOs vary significantly between different stars. In particular, we predict a strong correlation between an ISO's ammonia abundance and its parent star's metallicity: high-metallicity stars will create ISOs rich in ammonia. This suggests the production rates of NH$_3$'s photolytic daughter products are an ideal observational tracer for the origins of ISOs. We infer that 2I/Borisov formed around a star of near-solar metallicity ($-0.4\lesssim[\mathrm{Fe}/\mathrm{H}]\lesssim0.3$), and corroborate the velocity- and isotope-based inferences that 3I/ATLAS formed around a lower-metallicity star ($-0.8\lesssim[\mathrm{Fe}/\mathrm{H}]\lesssim0.0$). The production rates of 2I and 3I imply both only contain hypervolatiles such as CO and N$_2$ that are trapped in other less-volatile ices, similar to typical Solar System comets. Despite this, we argue that true hypervolatile-ice-rich ISOs may exist; they would exhibit high CO and N$_2$ production rate ratios, possibly similar to those of C/2016 R2 (PanSTARRS). Our predictions provide context for future ISO discoveries, opening a path to link the properties of their origin systems to observable production rates.
CommentsSubmitted to AJ
