![Column density maps of 13CO2, CO and OCN− ice (panel I, II and III, respectively). 12CO2 column densities are derived from 13CO2 column densities. Panel IV shows the ratio between the 4.38 µm and 4.39 µm peak of the 13CO2 ice feature. A higher ratio indicates higher degree of CO2 ice segregation. The axes are shown on astronomical unit scales. Pixelated areas especially in the north and south of the maps as well as the edges are caused by low signal-to-noise levels. -- [astro-ph.SR]](https://i0.wp.com/astrobiology.com/wp-content/uploads/2026/10/Mapping.png?fit=1200%2C675&ssl=1)
[astro-ph.SR] The composition of planets and their atmospheres is largely determined by the formation environment of the planet. This environment is pre-determined during early stages when the protostar is still forming.
Charting the structure of protostellar envelopes is therefore crucial for understanding how the chemistry is linked to the physical processes occurring in stellar nurseries.
We use JWST NIRSpec IFU observations to extract spectra at every pixel in the IFU and map the distribution of 13CO2,12CO2, CO, OCN− and H2O ice. The 13CO2 ice feature, a known thermal tracer, is also used to identify high-temperature regions where the ices are thermally processed.
The findings show that the distribution of ices in both L1527 and IRAS 20126+4104 is not uniform, with both envelopes showing localized temperature zones and substructures.
In L1527, CO2 ice segregation and OCN− enhancement with respect to CO2 are observed in the warm central disk region close to the protostar. In IRAS 20126+4104, the warm temperature zones are observed mostly towards the shocked region in the NW outflow where dense material is interacting with the precessing jet as well as close to the central source. The CO2 ice is segregated at these locations and we observe sublimation of CO ice. In addition, crystalline H2O ice is detected at a few locations in the envelope.
In both low mass and high mass protostar the findings indicate that the distribution of ices and their structure are linked to the temperature structure of the envelopes. The envelope of IRAS 20126 shows a more complex structure, where interacting material results in localized regions of high temperatures and denser regions that harbor cooler ices. L1527 in contrast appears to be a more structured system with heated warm ices observed mostly towards the central disk regions.
Schematic of the L1527 system. The molecular outflows observed with JWST NIRSpec. The SiO jets in L1527 (van’t Hoff et al. 2023) are illustrated in red while the disk is depicted in blue. The atomic and ionic emissions detected by Drechsler et al. (2026) in L1527 are depicted in purple and brown, respectively. The icy grains provide a summary of the main findings in this work. — [astro-ph.SR]
Schematic of the IRAS 20126 system. The molecular outflows observed with JWST NIRSpec. The SiO jets in IRAS 20126 (Cesaroni et al. 2025) are illustrated in red while the disk with the molecular C34S clump (Cesaroni et al. 1997) is depicted in blue. The dense gas in the NW region traced by DCN (Cesaroni et al. 2025) is shown in brown. The positions of the young stellar companions in IRAS 20126 are illustrated with two knots in pink. Finally, the icy grains provide a summary of the main findings in this work. — [astro-ph.SR]
N. G. C. Brunken, E. F. van Dishoeck, A. C. A. Boogert, P. Nazari, Y. Chen, J. Santos, H. Beuther, A. Caratti o Garatti, T. Megeath, K. Slavicinska, C. Gieser, H. Tyagi, L. Tychoniec, M. McClure, V. J. M. le Gouellec, Y. Yang, L. W. Looney, N. J. Evans, M. Narang
Subjects: Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2610.08491 [astro-ph.SR] (or arXiv:2610.08491v1 [astro-ph.SR] for this version)
https://doi.org/10.48550/arXiv.2610.08491
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Submission history
From: Nashanty Brunken
[v1] Tue, 6 Oct 2026 15:03:33 UTC (6,917 KB)
https://arxiv.org/abs/2610.08491
Astrobiology, Astrochemistry,
