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

Abstract

We present a study of molecular gas in the inner disk 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 Ly α -pumped H 2 . The result shows H 2 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 H 2 line shapes shows that a two-component Gaussian profile is statistically preferred to a single-component Gaussian. We interpret this as tentative evidence for gas emitting from radially separated disk regions . The 4.7 μ m 12 CO emission lines are also well fit by two-component profiles . We combine these results with 10 μ m 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.