Probing the Inner Disk Emission of the Herbig Ae Stars HD 163296 and HD 190073

The physical processes occurring within the inner few astronomical units of protoplanetary disks surrounding Herbig Ae stars are crucial to setting the environment in which the outer planet-forming disk evolves and put critical constraints on the processes of accretion and planet migration. We present the most complete published sample of high angular resolution H- and K-band observations of the stars HD 163296 and HD 190073, including 30 previously unpublished nights of observations of the former and 45 nights of the latter with the CHARA long-baseline interferometer, in addition to archival VLTI data. We confirm previous observations suggesting that significant near-infrared emission originates within the putative dust evaporation front of HD. 163296 and show that this is the case for HD 190073 as well. The H- and K-band sizes are the same within (3 +/- 3)% for HD 163296 and within (6 +/- 10)% for HD 190073. The radial surface brightness profiles for both disks are remarkably Gaussian-like with little or no sign of the sharp edge expected for a dust evaporation front. Coupled with spectral energy distribution analysis, our direct measurements of the stellar flux component at the H and K bands suggest that HD 190073 is much younger (<400 kyr) and more massive (similar to 5.6M(circle dot)) than previously thought, mainly as a consequence of the new Gaia distance (891 pc).