PDRs4All XXI. JWST-NIRCam Photometric properties of protoplanetary disks in the Orion Nebula Cluster

We use the high angular resolution NIRCam images from the PDRs4All program, combined with those of GTO program 1256, to extract key properties of disks in the Orion Nebula Cluster. We measure disk radii in silhouette against the bright background, identify dissociation fronts (DFs) and ionization fronts (IFs), determine Paschen $α$ intensities, and derive near-infrared spectral energy distributions (SEDs). From these diagnostics we define a typology of ONC disks. Type I sources show merged IFs and DFs close to the disk surface. Type II sources have DFs at the disk surface and IFs located tens of astronomical units away. Type III sources show a DF at the disk surface but no IF. For all types, PAH emission traces the PDR. We find that the disk radius $r_{\rm disk}$ increases with projected distance to the ionizing source $d_{\rm proj}$, following $r_{\rm disk} \propto d_{\rm proj}^{0.30}$, consistent with disk truncation by photoevaporation. Disk radii measured in the infrared are larger than those measured at millimeter wavelengths, suggesting radial dust segregation within the disks. In agreement with PDR models, the thermal pressure in the disk PDR increases with the FUV radiation field $G_0$, but with a flatter slope. Finally, the SEDs of candidate Jupiter Mass Binary Objects (JuMBOs) are similar to those of Type III disks, except for JuMBO24, which resembles a Type I or Type II source. Its SED is consistent with a young low-mass binary hosting an unresolved ionized disk.

💡 Research Summary

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This paper presents a comprehensive photometric study of protoplanetary disks in the Orion Nebula Cluster (ONC) using the unprecedented spatial resolution of JWST NIRCam. The authors combine data from the Early Release Science (ERS) program “PDRs4All” (PID 1288) and the Guaranteed Time Observation (GTO) program 1256, covering 14 and 12 NIRCam filters respectively, spanning 1.15 µm to 4.8 µm. After careful reduction (following Habart et al. 2024 and Luhman 2024), the combined dataset provides contiguous coverage of the Trapezium region and the surrounding nebular structures.

The sample of disks is built on the classic HST catalog of Ricci et al. (2008), which listed 219 silhouette proplyds. By cross‑matching with the JWST images the authors recover 188 of these objects, add three newly identified proplyds from recent PDRs4All work, and include one additional source (HC182) that shows a clear silhouette and bright cocoon in the Pa α filter. The final catalog contains 192 protoplanetary disks. In parallel, the authors revisit the population of Jupiter‑mass binary objects (JuMBOs) originally identified in the GTO 1256 data (Pearson & McCaughrean 2023). Only 11 of the 40 JuMBOs fall within the smaller PDRs4All fields, but these are sufficient for a comparative spectral analysis.

The authors exploit four key NIRCam filters to trace distinct physical components: F164N (