CO2 infrared emission as a diagnostic of planet-forming regions of disks

摘要: Context. The infrared ro-vibrational emission lines from organic molecules in the inner regions of protoplanetary disks are unique probes physical and chemical structure planet-forming processes that shape them. These observed mostly interpreted with local thermal equilibrium (LTE) slab models at a single temperature. Aims. We aim to study non-LTE excitation effects carbon dioxide (CO2 ) full disk model evaluate: (i) what emitting different CO2 bands are; (ii) how abundance can be best traced using future JWST data and; (iii) abundances tell us about physics chemistry. is major ice component its potentially test migrating icy pebbles across iceline.Methods. A has been built starting experimental theoretical molecular data. characteristics tested models. Subsequently line formation was modelled two-dimensional representative T Tauri where detected mid-infrared by Spitzer Space Telescope.Results. gas emits 15 μ m 4.5 spectrum not LTE arises upper layers disks, pumped radiation. v 2 feature dominated optically thick for most fit observations increases linearly source luminosity. Its narrowness compared other stems combination low rotational temperature (~ 250 K) inherently narrower . inferred derived range 3 × 10-9 1 10-7 respect total density typical gas/dust ratios 1000, similar earlier estimates. Line-to-continuum low, order few percent, stressing need high signal-to-noise (S /N > 300) individual detections.Conclusions. much lower than those found interstellar ices 10-5 ), indicating reset chemistry reactions disk. JWST-MIRI higher spectral resolving power will allow more accurate retrieval P - R -branch lines, together 13 Q m. particularly sensitive possible enhancements due sublimation iceline(s). Prospects JWST-NIRSpec discussed as well.