Mapping Icy Grains in AB Aur: Constraining Composition, Growth, and Filtration

The formation of planets within circumstellar disks is highly dependent on local disk conditions, (circum)stellar activity, and the distribution and phase of materials necessary for formation. One important key to interpreting observational signatures of planet formation is understanding the role icy grains play in the formation planets. Icy grains aid grain coagulation and thus planetesimal growth, making them an important component of giant planet formation. We use LBT LMIRCam data to map the transitional disk around the young (~4 Myr) Herbig Ae/Be star AB Aur at the 3.09 μm ice feature. This, together with surface brightness observations at bracketing wavelengths (K_s and L') allow us to probe the location(s) of the reservoirs of volatiles needed to build giant planet cores, as well as vertical substructure and compositional gradients in the disk. Color information allows us to constrain the size, composition, and location of icy grains within the disk, and this information in turn helps inform grain growth, grain filtration, and vertical mixing, in this young, planet-forming environment.