# JWST Imaging of Edge-on Protoplanetary Disks. IV. Mid-infrared Dust Scattering in the HH 30 disk

**Authors:** Ryo Tazaki, François Ménard, Gaspard Duchêne, Marion Villenave, Álvaro Ribas, Karl R. Stapelfeldt, Marshall D. Perrin, Christophe Pinte, Schuyler G. Wolff, Deborah L. Padgett, Jie Ma, Laurine Martinien, Maxime Roumesy  
**arXiv:** [2412.07523](https://arxiv.org/abs/2412.07523)  
**Date:** 2024-12-10  
**Summary page:** https://www.summarizepaper.com/en/arxiv-id/2412.07523v1/

## Key points

- Comprehensive analysis of the edge-on protoplanetary disk surrounding HH 30 using near- and mid-infrared broadband imaging observations
- Combination of observations from James Webb Space Telescope/NIRCam, MIRI, Hubble Space Telescope, and ALMA for unprecedented spatial resolution
- Revealing intricate details of disk structure, including vertical and radial segregation of grains
- Observation of bi-reflection nebulae, dynamic processes like spiral structures, conical outflow, and collimated jet within the disk
- Radiative transfer simulations to elucidate grain distribution within the disk
- Grains with radii around 3 µm or larger are fully vertically mixed; millimeter-sized grains settled into a layer with scale height exceeding 1 au at a distance of 100 au from central star
- Discrepancy in inferred disk inclination angle between optical/near-IR and mm observations suggesting an almost perfectly edge-on orientation
- Detection of proper motion in an emission knot associated with a mid-IR collimated jet by combining two epochs of MIRI 12.8 µm observations
- Findings provide valuable insights into complex dynamics and grain distribution within protoplanetary disks like HH 30, contributing to understanding planetary system formation in young stellar environments

## Summary

In this study, we present a comprehensive analysis of the edge-on protoplanetary disk surrounding HH 30 using near- and mid-infrared (IR) broadband imaging observations obtained with the James Webb Space Telescope/Near Infrared Camera (NIRCam) and the Mid-Infrared Instrument (MIRI). These observations are combined with archival optical/near-IR scattered light images from the Hubble Space Telescope (HST) and a millimeter-wavelength dust continuum image from the Atacama Large Millimeter/submillimeter Array (ALMA), providing unprecedented spatial resolution for this target. The multiwavelength images reveal intricate details of the disk structure, showcasing the vertical and radial segregation of micron-sized and sub-mm-sized grains. The near- and mid-IR images capture bi-reflection nebulae separated by a dark lane, as well as various dynamic processes within the HH 30 disk, including spiral- and tail-like structures, a conical outflow, and a collimated jet. Moreover, radiative transfer simulations are performed to elucidate the distribution of grains within the disk. The results indicate that grains with radii around 3 µm or larger are fully vertically mixed, explaining the observed mid-IR scattered light flux and morphology. On the other hand, millimeter-sized grains appear to be settled into a layer with a scale height exceeding 1 au at a distance of 100 au from the central star. Furthermore, there is an intriguing discrepancy in the inferred disk inclination angle between optical/near-IR and mm observations, with <kw>dust disk orientation</kw>, suggesting an almost perfectly edge-on orientation. Additionally, this study reports on detecting proper motion in an emission knot associated with a mid-IR collimated jet by combining two epochs of MIRI 12.8-µm observations. Overall, these findings provide valuable insights into the complex dynamics and grain distribution within protoplanetary disks like HH 30, shedding light on their formation and evolution processes. This detailed analysis contributes significantly to our understanding of <kw>planetary system formation</kw> in young stellar environments.