Mapping Interstellar Ice Inventory toward Class 0 Protostars in Star-forming Region Orion A with JWST Data

2026/06/08 by Igor Petrashkevich, Yaroslav Pavlyuchenkov, Anna Punanova +7 · 1 voice
Physics and Astronomy · #astro-ph.GA

paper · pdf · doi:10.3847/1538-4357/ae7b20

Abstract

We present a detailed study of the spatial distribution and chemical composition of interstellar ices toward six Class 0 protostars (HOPS-56, HOPS-60, HOPS-73, HOPS-91, HOPS-96, and HOPS-108) in the Orion A molecular cloud. Using high-resolution spectroscopic data from the JWST NIRspec and MIRI MRS instruments (4.3 - 8.1 μm), we have constructed the first pixel by pixel absorption maps with a resolution of ∼100~AU for key ice species, including ¹³CO₂, OCN^-, CO, H₂O, NH₄⁺, and H₂CO. CH₄ and OCS were analyzed toward the continuum peaks. The column densities were derived by fitting the observed spectra with laboratory ice analogs. We employed radiative transfer modeling, which confirmed the reliability of our column density estimates within the protostellar envelopes. Our analysis reveals significant variations in ice abundances and distributions, reflecting the physical structure and energetic processes within the envelopes. Specifically, we observe the influence of protostellar heating and outflows on the ice mantles, most notably in HOPS-60. The total ice composition is consistent with astrochemical models and covers ∼90% of observed ice inventory suggesting that ice is primarily formed during the prestellar stage and subsequently inherited by the protostellar envelope. Based on the abundance relative to water, the sources can be categorized into two distinct groups, possibly indicating evolutionary differences or variations in envelope density and temperature profiles.

Citations

• Formation of Complex Organic Molecules in Prestellar Cores: The Role of Non-Diffusive Grain Chemistry
• Expanding the Ice Inventory of NGC 1333 IRAS 2A with INDRA using JWST Observations: Tracing Organic Refractories and Beyond
• HDO ice detected toward an isolated low-mass protostar with JWST
• JWST Observations of Young protoStars (JOYS): overview of program and early results
• Solid and Gaseous Methane in IRAS 23385+6053 as seen with Open JWST Data
• JWST-IPA: Chemical Inventory and Spatial Mapping of Ices in the Protostar HOPS370 -- Evidence for an Opacity Hole and Thermal Processing of Ices
• Infrared Spectra of Solid HCN Embedded in Various Molecular Environments for Comparison with the Data Obtained with JWST
• JOYS+: mid-infrared detection of gas-phase SO₂ emission in a low-mass protostar. The case of NGC 1333 IRAS2A: hot core or accretion shock?
• PDRs4All
• Geometric distortion and astrometric calibration of the JWST MIRI Medium Resolution Spectrometer
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package*
• Influence of the magnetic field on the formation of protostellar disks
• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• Simultaneous Hydrogenation and UV-photolysis Experiments of NO in CO-rich Interstellar Ice Analogues; linking HNCO, OCN-, NH2CHO and NH2OH
• The Herschel Orion Protostar Survey: Spectral Energy Distributions and Fits Using a Grid of Protostellar Models
• The complex chemistry of outflow cavity walls exposed: the case of low-mass protostars
• Observations of the Icy Universe
• Astropy: A Community Python Package for Astronomy
• Evolution of Protostellar Outflow around Low-mass Protostar
• Stochastic grain heating and mid-infrared emission in protostellar cores
• Laboratory H2O:CO2ice desorption data: entrapment dependencies and its parameterization with an extended three-phase model
• Complex Organic Interstellar Molecules
• The Relation Between Optical Extinction and Hydrogen Column Density in the Galaxy
• Band profiles and band strengths in mixed H2O:CO ices
• The c2d Spitzer Spectroscopic Survey of Ices Around Low-Mass Young Stellar Objects: I. H2O and the 5-8 um Bands
• Fully Sampled Maps of Ices and Silicates in Front of Cepheus A East with Spitzer
• Effects of CO2 on H2O band profiles and band strengths in mixed H2O:CO2 ices
• Spatial mapping of ices in the Oph-F core: A direct measurement of CO depletion and the formation of CO2
• Mapping ices in protostellar environments on 1000 AU scales
• Origin of the 6.85 micron band near young stellar objects: The ammonium ion (NH4+) revisited
• The size distribution of interstellar grains

Discussions

• Mapping Interstellar Ice Inventory toward Class 0 Protostars in Star-forming Region Orion A with JWST Data Petrashkevich et al. arXiv (ApJ) arxiv.org/abs/2606.09776 [bsky, 0 points, 0 comments]

Related

• JWST-IPA: Chemical Inventory and Spatial Mapping of Ices in the Protostar HOPS370 -- Evidence for an Opacity Hole and Thermal Processing of Ices
• A Chemistry-First Centered Icy Chemical Inventory of Protostellar Sources with JWST
• A JWST inventory of protoplanetary disk ices: The edge-on protoplanetary disk HH 48 NE, seen with the Ice Age ERS program
• Interstellar Ices
• JWST Edge-on Disk Ice (JEDIce): Program overview and ice survey results