Presentation #321.03 in the session Laboratory Astrophysics (LAD) Division Meeting: A Universe of Carbon I.
The prominent 3.3, 6.2, 7.7, 8.6, and 11.3 μm emission bands of polycyclic aromatic hydrocarbons (PAHs) have been detected in protoplanetary disks (PPDs) around Herbig Ae/Be stars and T Tauri stars. The characteristics of the PAH emission bands of PPDs appear to be contingent on the stellar properties and the evolutionary phases of the disks. As their band ratios are sensitive to the charge state of PAHs, which is controlled by the electron density, gas temperature, and starlight intensity, the PAH emission bands can be used as a diagnostic tool of the physical conditions of PPDs. As a part of a systematic exploration of PAHs in PPDs, here we report our preliminary results on modeling the PAH emission in the disk around HD 97048, a 5-Myr-old Herbig Ae star, detected with the VISIR-NEAR longslit spectrometer on board the Very Large Telescope (VLT; see Yoffe et al. 2022). We model the 8.6 and 11.3 μm emission bands of PAHs, which are prominent in the disk and are recognizable up to ≈100-200 AU from the illuminating star. We determine the PAH size, charging and mass and their radial variations in the disk and discuss their implications for the disk structure and physical conditions.