Astrochemistry

Water Ice in the Edge-On Orion Silhouette Disk 114–426 from JWST NIRCam Images

By Keith Cowing

Status Report

astro-ph.EP

December 7, 2024

Filed under astro-ph.EP, astrochemistry, astronomy, biochemistry, Biosignatures, chemistry, dust grains, Interstellar, JWST/NIRCam, organic chemistry, Orion Nebula, Protoplanetary Disk, protoplanetary disk 114–426, Water

Water Ice in the Edge-On Orion Silhouette Disk 114–426 from JWST NIRCam Images — Left: Color composite image of 114–426 using the F115W and F140M (both blue), F162M (green), F182M (yellowgreen), and F277W (red) bands. Each of the four SW channel images (F115W, F140M, F162M, F182M) were interpolated onto a 3×3 pixel sub-grid (i.e. roughly 10 mas/pixel) to allow precise alignment, and the LW channel image (F277W) was resampled to match. Right: An image of 114–426 in the F187N band, again interpolated onto a 3 ×3 pixel sub-grid, showing the silhouette disk in maximum contrast against the Pa-α line. Each panel is 3.”5 × 3.”5 with north up and east left. The intensity of each image was scaled logarithmically to compress the dynamic range and enhance fainter details. — astro-ph.EP

We examine images of the protoplanetary disk 114–426 with JWST/NIRCam in 12 bands. This large disk is oriented edge-on with a dark midplane flanked by lobes of scattered light.

The outer edges of the midplane are seen in silhouette against the Orion Nebula, providing a unique opportunity to study planet-forming material in absorption. We discover a dip in the scattered light of the disk at 3 µm – compelling evidence for the presence of water ice.

The 3 µm dip is also seen in the silhouette of the disk, where we quantify the ice abundance with models of pure absorption and avoid the complications of disk scattering effects.

We find grain ice-to-refractory mass ratios of up to ∼0.2, maximum grain sizes of 0.25 to 5 µm, and a total dust plus ice mass of 0.46 M_⊕ in the silhouette region. We also discover excess absorption in the NIRCam bands that include the Paschen α line, suggesting there may be excited atomic hydrogen in the disk.

Examining the morphology of the scattered light lobes reveals that they are laterally offset from each other and exhibit a brightness asymmetry that flips with wavelength – both evidence for a tilted inner disk in this system.

Nicholas P. Ballering, L. Ilsedore Cleeves, Ryan D. Boyden, Mark J. McCaughrean, Rachel E. Gross, Samuel G. Pearson

Comments: 17 pages, 12 figures, accepted for publication in ApJ
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2412.04356 [astro-ph.EP] (or arXiv:2412.04356v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2412.04356
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Submission history
From: Nicholas Ballering
[v1] Thu, 5 Dec 2024 17:15:28 UTC (2,371 KB)
https://arxiv.org/abs/2412.04356
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) 🖖🏻

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