Issue |
A&A
Volume 696, April 2025
|
|
---|---|---|
Article Number | L6 | |
Number of page(s) | 6 | |
Section | Letters to the Editor | |
DOI | https://doi.org/10.1051/0004-6361/202554360 | |
Published online | 08 April 2025 |
Letter to the Editor
The role of absorption and scattering in shaping ice bands
Spatially resolved spectroscopy of protoplanetary disks
1
Univ. Grenoble Alpes, CNRS, IPAG, 38000 Grenoble, France
2
Astronomy Department, University of California Berkeley, Berkeley, CA 94720-3411, USA
3
Department of Earth Science and Astronomy, The University of Tokyo, Tokyo 153-8902, Japan
4
Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA
⋆ Corresponding author; laurine.martinien@univ-grenoble-alpes.fr
Received:
3
March
2025
Accepted:
19
March
2025
Aims. The James Webb Space Telescope now enables the spectral study of ices with unprecedented sensitivity and angular resolution. Water ice plays a crucial role in the growth of grains and in planetary formation but its spatial distribution in protoplanetary disks is poorly constrained. To aid the interpretation of future observations, we study here for the first time how the water ice band depends on the observer’s perspective and the location where spectra are measured within protoplanetary disks.
Methods. Based on a standard protoplanetary disk model around a T Tauri star, we used the radiative transfer code MCFOST to extract water-ice spectra and to measure the depth and central wavelength of the water-ice band at different locations in the disk.
Results. Even in the context of a spatially homogeneous ice mixture, the observed properties of water-ice bands depend on the inclination of the system as well as on the location in the disk from which the spectra are extracted. In particular, the wavelength of the band minimum can change by up to 0.17 μm, comparable to the difference expected between amorphous and crystalline ices, for instance. This phenomenon stems from a balance between absorption and scattering and must be taken into account in detailed modeling of spatially resolved infrared spectroscopy of ices, including CO and CO2.
Key words: scattering / protoplanetary disks / stars: variables: T Tauri / Herbig Ae/Be
© The Authors 2025
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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