Water UV-shielding in the Terrestrial Planet-forming Zone: Implications from Water Emission

Abstract Mid-infrared spectroscopy is one of the few ways to observe composition terrestrial planet-forming zone, inner astronomical units, protoplanetary disks. The species currently detected in disk atmosphere, for example, CO, CO 2 , H O, and C are theoretically enough constrain C/O ratio on surface. However, thermochemical models have difficulties reproducing full array mid-infrared simultaneously. In an effort get closer observed spectra, we included water UV-shielding as well more efficient chemical heating into code Dust Lines. We find that both required match emission spectrum. Efficient heating, addition traditional from UV photons, necessary elevate temperature water-emitting layer excitation water. stops photons reaching deep disk, cooling down lower layers with a higher column. These two effects create hot emitting column 1–10 × 10 18 cm ?2 . This only 1%–10% above dust ? = 1 surface at wavelengths represents <1% total