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Arxiv: JWST imaging of edge-on protoplanetary disks. III. Drastic morphological transformation across the mid-infrared in Oph163131 Published: 9/30/2024 10:00:02 PM Updated: 9/30/2024 10:00:02 PM
Paper abstract: We present JWST broadband images of the highly inclined protoplanetary diskSSTc2d J163131.2-242627 (Oph163131) from 2.0 to 21\mum. The images show aremarkable evolution in disk structure with wavelength, quite different fromprevious JWST observations of other edge-on disks. At 2.0 and 4.4\mum,Oph163131 shows two scattering surfaces separated by a dark lane, typical ofhighly inclined disks. Starting at 7.7\mum however, 1) the two linearnebulosities flanking the dark lane disappear; 2) the brighter nebula tracingthe disk upper surface transitions into a compact central source distinctlylarger than the JWST PSF and whose intrinsic size increases with wavelength;and 3) patches of extended emission appear at low latitudes, and atsurprisingly large radii nearly twice that of the scattered light seen withHST and NIRCam, and of the gas. We interpret the compact central source asthermal emission from the star and the inner disk that is not seen directly,but which instead is able to progressively propagate to greater distances atlonger wavelengths. The lack of sharp-edged structures in the extended patchyemission argues against the presence of shocks and suggests photoexcitation orstochastic heating of material smoothly flowing away from the star along thedisk surface. Finally, the dark lane thickness decreases significantly between0.6\mum and 4.4\mum which indicates that the surface layers of Oph163131lack grains larger than 1\mum.