THE DEPLETION OF WATER DURING DISPERSAL OF PLANET-FORMING DISK REGIONS
AffiliationUniv Arizona, Lunar & Planetary Lab
planets and satellites: formation
stars: pre-main sequence
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationTHE DEPLETION OF WATER DURING DISPERSAL OF PLANET-FORMING DISK REGIONS 2017, 834 (2):152 The Astrophysical Journal
JournalThe Astrophysical Journal
Rights© 2017. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at firstname.lastname@example.org.
AbstractWe present a new velocity-resolved survey of 2.9 mu m spectra of hot H2O and OH gas emission from protoplanetary disks, obtained with the Cryogenic Infrared Echelle Spectrometer at the VLT (R similar to 96,000). With the addition of archival Spitzer-IRS spectra, this is the most comprehensive spectral data set of water vapor emission from disks ever assembled. We provide line fluxes at 2.9-33 mu m that probe from the dust sublimation radius at similar to 0.05 au out to the region of the water snow line. With a combined data set for 55 disks, we find a new correlation between H2O line fluxes and the radius of CO gas emission, as measured in velocity-resolved 4.7 mu m spectra (R-co), which probes molecular gaps in inner disks. We find that H2O emission disappears from 2.9 mu m (hotter water) to 33 mu m (colder water) as R-co increases and expands out to the snow line radius. These results suggest that the infrared water spectrum is a tracer of inside-out water depletion within the snow line. It also helps clarify an unsolved discrepancy between water observations and models by finding that disks around stars of M-star > 1.5M(circle dot) generally have inner gaps with depleted molecular gas content. We measure radial trends in H2O, OH, and CO line fluxes that can be used as benchmarks for models to study the chemical composition and evolution of planet-forming disk regions at 0.05-20 au. We propose that JWST spectroscopy of molecular-gas may be used as a probe of inner disk gas depletion, complementary to the larger gaps and holes detected by direct imaging and by ALMA.
VersionFinal published version
SponsorsNASA Origins of the Solar System [OSS 11-OSS11-0120]; NASA Planetary Geology and Geophysics Program [NAG 5-10201]; European Union A-ERC grant [291141 CHEMPLAN]; National Aeronautics and Space Administration; W. M. Keck Foundation; ESO telescopes at the Paranal Observatory [179.C-0151, 093.C-0432, 088.C-0666, 079.C-0349, 081.C-0833, 091.C-0671, 082.C-0491, 088.C-0898]