Simple molecules and complex chemistry in a protoplanetary disk: A JWST investigation of the highly inclined disk d216-0939

Abstract

While the number of detected molecules, particularly complex organic molecules, in the solid-state in astrophysical environments is still rather limited, laboratory experiments and astrochemical models predict many potential candidates. Detection of molecules in protoplanetary disks provides a bridge between the chemical evolution of the interstellar medium and the chemistry of planets and their atmospheres. The excellent spectral sensitivity, broad wavelength coverage and high spatial resolution of the James Webb Space Telescope (JWST) allows for making progress in exploring chemical compositions of various astrophysical environments including planet-forming disks. They are a prerequisite for probing the disk content by means of sensitive absorption studies. In this paper, we present initial results of the JWST Cycle 1 GO program 1741 on d216-0939, a highly inclined TTauri disk located in the outskirts of the Orion Nebula Cluster. We utilise the NIRSpec and MIRI integral field unit spectrographs to cover its spectrum from 1.7 to 28~$\mu$m. In the d216-0939 disk, we give assignments of the composition of silicate grains. We unambiguously detect solid-state features of H$_2$O, CO$_2$, $^{13}$CO$_2$, CO, OCN$^-$, and tentatively OCS; species that had been detected recently also in other circumstellar disks. For the first time in disks, we provide unique detections of ices carrying NH$_4^+$ and the complex organic molecule ammonium carbamate (NH$_4^+$NH$_2$COO$^-$). The latter detections speak for a very efficient NH$_3$ chemistry in the disk. We also show the very important role of scattering in the analysis of observational spectra of highly inclined disks.