CO ro-vibrational lines in HD100546 - A search for disk asymmetries and the role of fluorescence
The inner regions of protoplanetary disks are excellent laboratories to study the formation of planets. At high spectral resolution, line profiles of various gas species contain a wealth of physical, chemical and kinematic information. The CO ro-vibrational lines, around 4.7 μm have been shown to originate in the innermost regions of disks where planets might be forming. Holes or gaps due to planet formation can be directly traced in the line profiles of these CO ro-vibrational transitions. However, this requires a firm understanding of the chemistry, excitation and line radiative transfer.
I will present a large comprehensive dataset with eight different position angles covering the well studied protoplanetary disk around HD100546, with an existing well calibrated model (2D structure of physics and chemistry). This analysis and comparison serves as a testbed for putting the CO ro-vib diagnostic on firm footings. Comparing observations and model, we investigate the possibility of disk asymmetries, the excitation mechanism (UV fluorescence), the geometry, gas scale heights, mass distribution and temperatures of the inner disk.