Spatially Resolving the Inner Disk of TW Hya

Abstract

We present Keck Interferometer observations of TW Hya that spatially resolve its emission at 2 micron wavelength. Analyzing these data together with existing K-band veiling and near-infrared photometric measurements, we conclude that the inner disk consists of optically thin, sub-micron-sized dust extending from ~4 AU to within 0.06 AU of the central star. The inner disk edge may be magnetospherically truncated. Even if we account for the presence of gas in the inner disk, these small dust grains have survival times against radiation blow-out that are orders of magnitude shorter than the age of the system, suggesting continual replenishment through collisions of larger bodies.