A UV-to-NIR Study of Molecular Gas in the Dust Cavity around RY Lupi

We present a study of molecular gas in the inner disk (r< 20 {au}) 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 ±15 km s‾¹; FWHM(narrow,H₂)=43± 13 km 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± 0.1 au; {r(narrow,H₂)} ∼ 3± 2 au). The 4.7 μm ¹²CO emission lines are also well fit by two-component profiles ( {{r}broad,CO} =0.4± 0.1 au; {{r}narrow,CO} =15± 2 au). 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.