论文标题
理论冰的实验室光谱：JWST的预测和天文学模型的测试
Laboratory spectroscopy of theoretical ices: Predictions for JWST and test for astrochemical models
论文作者
论文摘要
语境。前几年进行的几项观察和建模研究的主题是遗前核心L1544的气体和冰粒化学。冰壳的化学成分反映了沿时间进化的环境物理变化。调查结果暗示了星际冰的分层结构，其内层主要是h $ _2 $ o，并且在表面附近越来越多的CO。星际冰类似物的形态可以实验研究。目标。这项研究提出了一种三维拟合的新方法，其中观察结果首先与气体谷物化学模型拟合在一起。然后，基于数值结果，在分层和混合形态中的星际冰类似物中记录了实验室IR光谱。然后可以将这些结果与未来的James Webb太空望远镜（JWST）观察进行比较。特别注意包括IR不活跃的物种n $ _2 $和o $ _2 $。方法。使用傅立叶变换红外光谱仪，在10 K的温度下记录了包含最丰富预测分子的冰模拟光谱。 In the case of layered ice we deposited a H$_2$O-CO-N$_2$-O$_2$ mixture on top of a H2O-CH$_3$OH-N$_2$ ice, while in the case of mixed ice we examined a H$_2$O-CH$_3$OH-N$_2$-CO composition.结果。随着冰的变化和结构的变化，我们发现大多数检查的振动模式的吸收带的差异。 IR谱带曲线观察到的变化的程度将使我们能够从JWST的未来观察结果中分析L1544中冰披风的结构。结论。我们的光谱测量与即将进行的JWST观测的比较至关重要，对于对灰尘冰层的化学和物理结构进行严格的限制并解释了表面化学。
Context. The gas and ice-grain chemistry of the pre-stellar core L1544 has been the subject of several observations and modelling studies conducted in the past years. The chemical composition of the ice mantles reflects the environmental physical changes along the temporal evolution. The investigation outcome hints at a layered structure of interstellar ices with mainly H$_2$O in the inner layers and an increasing amount of CO near the surface. The morphology of interstellar ice analogues can be investigated experimentally. Aims. This research presents a new approach of a three-dimensional fit where observational results are first fitted with a gas-grain chemical model. Then, based on the numerical results the laboratory IR spectra are recorded for interstellar ice analogues in a layered and in a mixed morphology. These results can then be compared with future James Webb Space Telescope (JWST) observations. Special attention is paid to the inclusion of the IR inactive species N$_2$ and O$_2$. Methods. Ice analogue spectra containing the most abundant predicted molecules were recorded at a temperature of 10 K using a Fourier transform infrared spectrometer. In the case of layered ice we deposited a H$_2$O-CO-N$_2$-O$_2$ mixture on top of a H2O-CH$_3$OH-N$_2$ ice, while in the case of mixed ice we examined a H$_2$O-CH$_3$OH-N$_2$-CO composition. Results. Following the changing composition and structure of the ice, we find differences in the absorption bands for most of the examined vibrational modes. The extent of observed changes in the IR band profiles will allow us to analyse the structure of ice mantles in L1544 from future observations by the JWST. Conclusions. The comparison of our spectroscopic measurements with upcoming JWST observations is crucial in order to put stringent constraints on the chemical and physical structure of dust icy mantles, and to explain surface chemistry.
