2018ApJ...855...98A

We present a study of molecular gas in the inner disk (r< 20au) around RY Lupi, with spectra from HST-COS, HST-STIS, and VLT-CRIRES. We model the radial distribution of flux from hot gas in a surface layer between r = 0.1-10 au, as traced by Lyα-pumped H₂. The result shows H₂ emission originating in a ring centered at ∼3 au that declines within r < 0.1 au, which is consistent with the behavior of disks with dust cavities. An analysis of the H₂ line shapes shows that a two-component Gaussian profile (FWHM_broad,H2_=105±15km s^–1;FWHM_narrow,H2_=43±13km s^–1) is statistically preferred to a single-component Gaussian. We interpret this as tentative evidence for gas emitting from radially separated disk regions (<r_broad,H2_>∼0.4±0.1au;<r_narrow,H2_>∼3±2au). The 4.7 µm ¹²CO emission lines are also well fit by two-component profiles (<r_broad,CO>=0.4±0.1au;<r_narrow,CO>=15±2au). We combine these results with 10 µm observations to form a picture of gapped structure within the mm-imaged dust cavity, providing the first such overview of the inner regions of a young disk. The HST SED of RY Lupi is available online for use in modeling efforts.