2018ApJ...869..164S

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of high angular resolution H- and K-band observations of the stars HD 163296 and HD 190073, including 30 previously unpublished nights of observations of the former and 45 nights of the latter with the CHARA long-baseline interferometer, in addition to archival VLTI data.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 (∼5.6 M_☉) than previously thought, mainly as a consequence of the new Gaia distance (891 pc).