News Summary Archives

Water Ice In The Debris Disk Around HD 181327

By Keith Cowing

Status Report

astro-ph.EP

May 15, 2025

Filed under astro-ph.EP, astrochemistry, exoKuiper belt, exoplanet, HD 181327, KBO, Kuiper Belt, Protoplanetary Disk, Spectroscopy, Water

Water Ice In The Debris Disk Around HD 181327 — Disk reflectance spectra at different stellocentric distances. a, The disk reflectance spectra at 80- 90 au (region 1, yellow), 90-105 au (region 2, orange), and 105-120 au (region 3, cyan), as shown in panel b. Disk reflectance spectra extracted from 80-90 au are dominated by a mixture of olivine and FeS, 90-105 au show the clear presence of water ice at ~3 µm and a Fresnel peak at 3.1 µm, and 105-120 au show more water ice and a deeper band depth at ~4.5 µm. The best-fit dust models are shown in gray. The corresponding model parameters are listed in Table 1. b, The disk image (0.6–5.2 µm combined) of HD 181327 after the removal of the stellar PSF. Different apertures (marked as 1, 2, and 3 and corresponding to the colors in panel a) were used to explore the dust gradients in the radial direction. The location of the star is marked with a magenta cross. The residuals of diffraction spikes and the central region are masked in gray. The dark horizontal strip in the image is an artifact caused by detector saturation. — astro-ph.EP

Debris disks are exoplanetary systems that contain planets, minor bodies (i.e., asteroids, Kuiper belt objects, comets, etc.), and micron-sized debris dust.

Since water ice is the most common frozen volatile, it plays an essential role in the formation of planets and minor bodies. Although water ice has been commonly found in Kuiper belt objects and comets in the Solar System, no definitive evidence for water ice in debris disks has been obtained to date.

Here, we report the discovery of water ice in the HD 181327 disk using the James Webb Space Telescope Near-Infrared Spectrograph.

We detect the solid-state broad absorption feature of water ice at 3 μm and a distinct Fresnel peak feature at 3.1 μm, a characteristic of large water-ice particles. This implies the presence of a water-ice reservoir in the HD 181327 exoKuiper belt.

Gradients of water-ice features at different stellocentric distances reveal a dynamic process of destroying and replenishing water ice in the disk, with estimated water-ice mass fractions ranging from 0.1% at ~85 au to 14% at ~113 au.

It is highly plausible that the icy bodies that release water ice in HD 181327 could be the extra-solar counterparts of some of the Kuiper belt objects in our Solar System, supported by their spectral similarity.

Spectral comparison between the HD 181327 disk and icy KBOs. After removing the slope created by FeS and olivine (Methods and Extended Data Fig. 8), we obtain the water-ice-dominated disk spectrum at 90-120 au. For comparison, the water-ice-rich KBO spectra are also shown, adopted from ref. 17. The HD 181327 spectrum shows a feature at 4.268 µm that may be a possible detection of CO2 ice.Although the band depths of water ice are different potentially caused by different grain sizes, the two kinds of spectra show striking similarities, considering the fact that the two spectra came from different sources (i.e., micron-sized dust grains in an exoKuiper belt and the surface of KBO in the Solar System). The location of the Fresnel peak at 3.1µm is marked by the vertical dashed line. — astro-ph.EP

Chen Xie, Christine H. Chen, Carey M. Lisse, Dean C. Hines, Tracy Beck, Sarah K. Betti, Noemí Pinilla-Alonso, Carl Ingebretsen, Kadin Worthen, András Gáspár, Schuyler G. Wolff, Bryce T. Bolin, Laurent Pueyo, Marshall D. Perrin, John A. Stansberry, Jarron M. Leisenring

Comments: Published in Nature on May 14th, 2025, Water Ice In The Debris Disk Around HD 181327
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2505.08863 [astro-ph.EP] (or arXiv:2505.08863v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2505.08863
Focus to learn more
Related DOI:
https://doi.org/10.1038/s41586-025-08920-4
Focus to learn more
Submission history
From: Chen Xie
[v1] Tue, 13 May 2025 18:00:01 UTC (8,850 KB)
https://arxiv.org/abs/2505.08863
Astrobiology, Astrochemistry,

Keith Cowing

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 veteran, (he/him) 🖖🏻

Follow on Twitter