Grain Growth-Induced Curvature of the Inner Rim of Protoplanetary Disks

Milliarcsecond resolution near infrared (NIR) interferometry of Herbig AeBe stars revealed a size-luminosity relation, indicating the circumstellar component arose from a dust sublimation rim, Rsub. However, evidence is mounting from e.g. NIR spectro-interferometry that optically thick material also exists interior to Rsub. Here, I present results from our comprehensive analysis of the spectral energy distribution (SED) and NIR interferometry of HD142666 using geometric and radiative transfer models. Our dataset offers the most complete uv-plane coverage obtained for a Herbig AeBe star across the NIR, featuring previously unpublished 330m-baseline CHARA Array data, allowing us to place strong constraints on the disk viewing geometry. We find that disk models incorporating grain growth to micron-size in the inner au are required to simultaneously fit the SED and visibilities. Furthermore, models in which rim curvature arises due to the sublimation temperature's dependence on gas density better fit the data than those where curvature arises due to grain growth-induced dust settling. Contrary to prior studies, we find no direct indication of optically thick material interior to Rsub.