Speaker
Description
Interstellar ices on dust-grain surfaces play a crucial role in the chemical evolution of molecular clouds and the formation of complex molecules. Their composition and microscopic structure provide insights into the physical and chemical conditions of star-forming environments. In this work, we independently analyse publicly available James Webb Space Telescope (JWST)/NIRCam spectroscopic observations of 44 lines of sight through the Chamaeleon I molecular cloud, originally studied by Smith et al. (2025), to investigate the spatial distribution of H₂O, CO₂, and CO ices and examine additional spectral features associated with ice structure.
We independently retrieve and process the infrared spectra, fit the underlying continua using polynomial models, and estimate ice column densities from the absorption bands near 3.0 μm (H₂O), 4.27 μm (CO₂), and 4.67 μm (CO). The derived column densities are used to construct spatial distribution maps, investigate correlations between ice species, and examine their relative abundances through ternary composition analysis.
The analysis reveals distinct spatial distributions of the three ice components, with H₂O ice widespread across the mapped region and CO ice showing a more spatially concentrated distribution. The median CO₂/H₂O and CO/H₂O column-density ratios are approximately 0.25 and 0.32, respectively, consistent with the corresponding literature values of approximately 0.29 and 0.34. The ternary composition analysis reveals a predominantly H₂O-rich population alongside a smaller spread of CO₂-rich and CO-rich sightlines. The examination of the dangling OH feature complements these abundance measurements by extending the analysis from ice composition to the physical structure of the ice itself.
This work demonstrates how independent analysis of spatially resolved infrared spectra can investigate both the chemical diversity and microscopic properties of interstellar ice mantles, providing further insight into the evolution of molecular clouds.
Other Fields of Research (Track) for Abstract
Astrochemistry
| Nature of work | Computational |
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