Discovery of CO Gas in the Inner Disk of TW Hydrae

Abstract

We report the detection of rovibrationally excited CO emission from the inner disk of the classical T Tauri star (cTTS) TW Hya. We observe ~6×1021 g of CO gas with a rotational temperature of 430+/-40 K. The linearity of the excitation plot suggests that the CO is optically thin. Atypical for cTTSs, hot CO was not detected, implying that TW Hya has cleared its inner disk region out to a radial distance of ~0.5 AU. We discuss implications for the structure of the disk as it relates to replenishment and planet formation.