Spatial distribution of water ice in the protoplanetary silhouette disk d216-0939

The composition of rocky planets depends on the dust in their natal protoplanetary disk (PPD), potentially containing water ice. Crystalline water ice was detected in the PPD d216-0939 in the Orion Nebular Cluster (ONC). We aim at constraining the spatial distribution and crystallization state of water ice in the d216-0939 disk using recent observations of the water ice absorption feature at a wavelength of $\sim 3\mathrm{μm}$ collected with JWST. We perform 3D Monte Carlo radiative transfer (MCRT) simulations to constrain the free parameters of an accretion disk model by fitting the calculated spectrum in the wavelength range from $1.6 \text{ to } 24\mathrm{μm}$ to the spectral energy distribution (SED) observed with the JWST instruments NIRSpec and MIRI. Additionally, archival, spatially resolved HST observations were used to constrain the global spatial structure of the disk, as the parameter space is degenerate with respect to the fit to the SED. Successively, we fit the water ice absorption feature using polychromatic MCRT simulations with spectral importance sampling to produce synthetic observations at high spectral resolutions. By probing the upper and outer disk layers, we found that a PPD model with dust containing 5.4% crystallized water ice beyond the snowline fits the observations well, necessitating outward transport of material, since crystalline ice is unlikely to form in situ in the probed disk layers. In the spectral region of the water ice absorption feature, scattering and thermal dust emission both contribute significantly to the total flux.

Source: arXiv:2608.04803v1 - http://arxiv.org/abs/2608.04803v1 PDF: https://arxiv.org/pdf/2608.04803v1 Original Link: http://arxiv.org/abs/2608.04803v1