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Researchers have detected HDO (deuterated water) ice in a protoplanetary disk for the first time using JWST observations of disk 132-1832 in the Orion Nebula Cluster. The HDO/H₂O ratio found in this disk is significantly higher than ratios observed in chondrites, comets, and young stellar objects. Additional ice species detected include H₂O, CO₂, ¹³CO₂, CO, OCN⁻, and OCS.
Why it matters
This discovery helps scientists trace the chemical evolution from interstellar clouds to planetary systems, providing insights into how water and its deuterium enrichment are inherited during planet formation. Understanding these processes is crucial for determining the chemical composition of planets and their atmospheres.
arXiv:2606.10888v1 Announce Type: cross
Abstract: 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. 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/H$_2$O ratio for 132-1832 is much higher, compared to HDO/H$_2$O ratios obtained for chondrites, comets, and embedded young stellar objects. In the disk ices, beyond HDO, we detected H$_2$O, CO$_2$, $^{13}$CO$_2$, 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.