论文标题
测量毫米波长的原星磁盘中的元素丰度比
Measuring elemental abundance ratios in protoplanetary disks at millimeter wavelengths
论文作者
论文摘要
在数百万年的进化中，可以在化学上重新加工原动性磁盘中的气尘和冰。有证据表明，气相碳和氧气丰度是属于附近恒星形成区域的磁盘中的亚磨牙。这些发现对巨型行星的主要大气的组成有重大影响（但它也可能对超级地点和亚核）有效，因为它们会从磁盘中的周围材料中积聚气体信封。在这项研究中，我们进行了热化学建模分析，目的是测试基于分子线的（亚）毫米观测值的元素丰度比的可靠性和稳健性。我们为以下不同的元素丰度比创建了磁盘模型的网格：c/o，n/o和s/o，并且我们计算了一组碳，氮和含硫物种的线路通量，即CN，hcn，hcn，no，no，no，c $ _ _ {2} $ _ {2} $ h，c-c $ __，c $ _} $ _ {3} $ {3} $ {3} $ {3} $ {3} $ {3} $ {2} h $ _ {2} $ co，hc $ _ {3} $ n，ch $ _ {3} $ cn，cs，so，so，h $ _ {2} $ s和h $ _ {2} $ cs，已通过当前的（子）毫米和noema（例如Alma和Noema）检测到。我们发现，曾经将线路通标准化到$^{13} $ co $ j = 2-1 $ line的通量，对元素丰度比率很敏感。另一方面，恒星和磁盘物理参数仅具有线路比率的较小效果。我们的结果表明，对多个分子跃迁的同时分析是限制原动性磁盘中元素丰度比的有效方法。
During the million years of evolution, gas dust and ice in protoplanetary disks can be chemically reprocessed. There are evidences that the gas-phase carbon and oxygen abundances are sub-solar in disks belonging to nearby star forming regions. These findings have a major impact on the composition of the primary atmosphere of giant planets (but it may also be valid for super-Earths and sub-Neptunes) as they accrete their gaseous envelopes from the surrounding material in the disk. In this study, we performed a thermo-chemical modelling analysis with the aim at testing how reliable and robust are the estimates of elemental abundance ratios based on (sub-)millimeter observations of molecular lines. We created a grid of disk models for the following different elemental abundance ratios: C/O, N/O and S/O, and, we computed the line flux of a set of carbon-, nitrogen and sulphur-bearing species, namely CN, HCN, NO, C$_{2}$H, c--C$_{3}$H$_{2}$, H$_{2}$CO, HC$_{3}$N, CH$_{3}$CN, CS, SO, H$_{2}$S and H$_{2}$CS, that have been detected with present (sub-)millimeter facilities such as ALMA and NOEMA. We find that the line fluxes, once normalized to the flux of the $^{13}$CO $J=2-1$ line, are sensitive to the elemental abundance ratios. On the other hand, the stellar and disk physical parameters have only a minor effect of the line flux ratios. Our results demonstrate that a simultaneous analysis of multiple molecular transitions is a valid approach to constrain the elemental abundance ratio in protoplanetary disks.
