JWST Ice Band Profiles Reveal Mixed Ice Compositions in the HH 48 NE Disk
Name
Bergner_2024_ApJ_975_166.pdf
Description
Published version
Size
2.08 MB
Format
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Checksum (MD5)
ee21a5207e2b6fef19821f07e4d2082c
Author(s)
Bergner, Jennifer B
Sturm, JA
Piacentino, Elettra L
McClure, MK
Öberg, Karin I
Boogert, ACA
Dartois, E
Drozdovskaya, MN
Fraser, HJ
Harsono, Daniel
Date Issued
October 31, 2024
Journal
The Astrophysical Journal
Publisher
American Astronomical Society
Citation
Jennifer B. Bergner et al 2024 ApJ 975 166
Version
Final published version
Abstract
Planet formation is strongly influenced by the composition and distribution of volatiles within protoplanetary disks. With JWST, it is now possible to obtain direct observational constraints on disk ices, as recently demonstrated by the detection of ice absorption features toward the edge-on HH 48 NE disk as part of the Ice Age Early Release Science program. Here, we introduce a new radiative transfer modeling framework designed to retrieve the composition and mixing status of disk ices using their band profiles, and apply it to interpret the H2O, CO2, and CO ice bands observed toward the HH 48 NE disk. We show that the ices are largely present as mixtures, with strong evidence for CO trapping in both H2O and CO2 ice. The HH 48 NE disk ice composition (pure versus polar versus apolar fractions) is markedly different from earlier protostellar stages, implying thermal and/or chemical reprocessing during the formation or evolution of the disk. We infer low ice-phase C/O ratios around 0.1 throughout the disk, and also demonstrate that the mixing and entrapment of disk ices can dramatically affect the radial dependence of the C/O ratio. It is therefore imperative that realistic disk ice compositions are considered when comparing planetary compositions with potential formation scenarios, which will fortunately be possible for an increasing number of disks with JWST.
MIT Department
Massachusetts Institute of Technology. Department of Chemistry
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Creative Commons Attribution
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DOI of Published Version
https://doi.org/10.3847/1538-4357/ad79fc
