Protoplanetary disks are the birthplace of planets and planetary systems. Investigating the molecular inventory of disks is key to linking the chemical evolution of the interstellar medium and the makeup of planets and their atmospheres.

In particular, tracing the history of the deuterium enrichment of water along the journey from interstellar clouds through protoplanetary disks to planetary systems provides critical insights into the chemical inheritance. We aim to investigate the chemical composition of ices in protoplanetary disks; specifically, the presence of HDO ice that ought to be present, but has not been detected in disks thus far.

Semiheavy water (HDO or HOD) Deuterium hydrogen monoxide is a naturally occurring chemical variant of water. (2H1)Water — Wikipedia

We analyzed JWST/NIRSpec observations of the 132-1832 edge-on disk located in the Orion Nebula Cluster using the ENIIGMA fitting tool and unique laboratory data. We report on the first detections of HDO ice in a protoplanetary disk. The estimated upper limit for the HDO/H2O ratio for 132-1832 is much higher, compared to HDO/H2O ratios obtained for chondrites, comets, and embedded young stellar objects.

In the disk ices, beyond HDO, we detected H2O, CO2, 13CO2, CO, OCN−, and OCS, species, whose presence has also been detected in other disks. The HDO ice detection may point to the efficient ice processing in the disk and confirm the findings of laboratory experiments on deuterated ices.

Alexey Potapov, Piyush Kalambkar, Jeroen Bouwman, Christiaan Boersma, Hiroshi Terada, Will R. Rocha, Hendrik Linz

Comments: Accepted by Astronomy & Astrophysics, 12 pages, 6 figures, 6 tables
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR); Chemical Physics (physics.chem-ph); Space Physics (physics.space-ph)
Cite as: arXiv:2606.10888 [astro-ph.EP](or arXiv:2606.10888v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2606.10888
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Related DOI:
https://doi.org/10.1051/0004-6361/202659525
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Submission history
From: Hendrik Linz
[v1] Tue, 9 Jun 2026 14:02:17 UTC (2,142 KB)
https://arxiv.org/abs/2606.10888

Astrobiology, Astrochemistry,

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp...