论文标题
通过天体物理冰的丰度跟踪质子的进化阶段
Tracking the evolutionary stage of protostars by the abundances of astrophysical ices
论文作者
论文摘要
年轻恒星物体（YSO）的物理演变伴随着分子复杂性的富集，这主要是由天体物理冰的加热和能量加工引起的。在本文中，已经对冰柱密度在整个原始的演化中的变化进行了研究。 h $ _2 $ o，co $ _2 $，ch $ _3 $ oh的列表数据，由基于空间和空间的望远镜观察到27个早期YSO，从文献中获取。观察数据表明，用于对进化阶段进行分类的冰柱密度和频谱指数（$α$）良好相关。 2D连续辐射传递模拟，其中包含不同水平的宇宙射线处理覆盖的裸露和晶粒，以在面对面和边缘构型之间以不同的角度倾斜的方式计算光谱能量分布（SED）。 H $ _2 $ O：CO $ _2 $冰混合物用于解决H $ _2 $ O和CO $ _2 $圆柱密度变化，而CH $ _3 $ OH，HCOOH是在能量处理后的Virgin Ice的副产品。模拟光谱用于计算进化序列中YSO的冰柱密度。结果，模型表明，使用$α$的HCOOH的冰柱密度变化可以通过包络耗散和冰的能量处理来证明。另一方面，即使考虑了物理和宇宙射线处理效果，冰柱的密度大多被高估了。
The physical evolution of Young Stellar Objects (YSOs) is accompanied by an enrichment of the molecular complexity, mainly triggered by the heating and energetic processing of the astrophysical ices. In this paper, a study of how the ice column density varies across the protostellar evolution has been performed. Tabulated data of H$_2$O, CO$_2$, CH$_3$OH, HCOOH observed by ground- and space-based telescopes toward 27 early-stage YSOs were taken from the literature. The observational data shows that ice column density and spectral index ($α$), used to classify the evolutionary stage, are well correlated. A 2D continuum radiative transfer simulation containing bare and grains covered by ices at different levels of cosmic-ray processing were used to calculate the Spectral Energy Distributions (SEDs) in different angle inclinations between face-on and edge-on configuration. The H$_2$O:CO$_2$ ice mixture was used to address the H$_2$O and CO$_2$ column density variation whereas the CH$_3$OH and HCOOH are a byproduct of the virgin ice after the energetic processing. The simulated spectra were used to calculate the ice column densities of YSOs in an evolutionary sequence. As a result, the models show that the ice column density variation of HCOOH with $α$ can be justified by the envelope dissipation and ice energetic processing. On the other hand, the ice column densities are mostly overestimated in the cases of H$_2$O, CO$_2$ and CH$_3$OH, even though the physical and cosmic-ray processing effects are taken into account.
