吸積冰晶中的CO譜線輪廓
The Astrophysical Journal 1003 (2026) 3
Rashida Aslam, Chun-Yi Lee, Yi-Hsuan Chiu, Cesare Cecchi-Pestellini, Angela Ciaravella, Antonio Jiménez-Escobar, Alfonso Mangione, and Yu-Jung Chen
CO Line Profiles in Accreting Ices
本研究以實驗室天文化學方法，系統探討CO冰在不同形成條件下，其紅外吸收光譜如何反映星際冰層的化學組成與結構演化。陳俞融教授指導的研究團隊與義大利合作研究團隊透過兩種沉積模式—固定低溫混合沉積，以及模擬星塵冷卻歷程的降溫分層沉積—建立含H2O、NH3、CH4、CO2與CH3OH的多組冰樣本，並結合高解析紅外光譜與Gaussian分解方法，建立43組CO微環境光譜資料庫。進一步應用於James Webb Space Telescope（JWST）觀測資料後發現，分子雲與原行星盤中的CO冰層，其光譜特徵主要由少數幾種關鍵微環境所主導。此成果提供了解析星際冰層形成歷史、化學分層與熱演化的重要光譜診斷工具，並為未來多成分星際冰研究奠定基礎。
Using a laboratory astrochemistry approach, this study systematically investigates how the infrared absorption spectra of CO ice formed under different conditions reflect the chemical composition and structural evolution of interstellar ice mantles. Under the guidance of Professor Yu-Jung Chen, the research team, in collaboration with Italian partners, employed two deposition protocols—fixed low-temperature mixed deposition and temperature-decreasing layered deposition simulating the cooling history of interstellar dust grains—to produce multiple ice samples containing H2O, NH3, CH4, CO2, and CH3OH. By combining high-resolution infrared spectroscopy with Gaussian decomposition analysis, the team established a spectral library of 43 distinct CO microenvironments. When further applied to observational data from the James Webb Space Telescope (JWST), the results revealed that the spectral characteristics of CO ice in molecular clouds and protoplanetary disks are primarily governed by only a few key microenvironments. These findings provide an important spectroscopic diagnostic framework for reconstructing the formation history, chemical stratification, and thermal evolution of interstellar ice mantles, while also laying the foundation for future studies of multicomponent interstellar ices.