An Unusual Reservoir of Water Emission in the VV CrA A Protoplanetary Disk

<jats:title>Abstract</jats:title> <jats:p>We present an analysis of an unusual pattern of water vapor emission from the ∼2 Myr old low-mass binary system VV CrA, as observed in IR spectra obtained with VLT-CRIRES, VLT-VISIR, and Spitzer-IRS. Each component of the binary shows emission from water vapor in both the <jats:italic>L</jats:italic> (∼3 <jats:italic>μ</jats:italic>m) and <jats:italic>N</jats:italic> (∼12 <jats:italic>μ</jats:italic>m) bands. The <jats:italic>N</jats:italic>-band and Spitzer spectra are similar to those previously observed from young stars with disks and are consistent with emission from an extended protoplanetary disk. Conversely, the CRIRES <jats:italic>L</jats:italic>-band data of VV CrA A show an unusual spectrum, which requires the presence of a water reservoir with high temperature (<jats:italic>T</jats:italic> ≳ 1500 K), column density (<jats:italic>N</jats:italic> <jats:sub>H2O</jats:sub> ∼ 3 × 10<jats:sup>20</jats:sup> cm<jats:sup>−2</jats:sup>), and turbulent broadening (<jats:italic>v</jats:italic> ∼ 10 km s<jats:sup>−1</jats:sup>) but very small emitting area (<jats:italic>A</jats:italic> ≲ 0.005 au<jats:sup>2</jats:sup>). Similarity to previously observed water emission from V1331 Cyg and SVS 13 suggests that the presence of such a reservoir may be linked to evolutionary state, perhaps related to the presence of high accretion rates or winds. While the inner disk may harbor such a reservoir, simple Keplerian models do not match well with emitting line shapes, and alternative velocity fields must be considered. We also present a new idea, that the unusual emission could arise in a circumplanetary disk, embedded within the larger VV CrA A protoplanetary disk. Additional data are likely required to determine the true physical origin of this unusual spectral pattern.</jats:p>