Water depletion in the disk atmosphere of Herbig AeBe stars

Abstract

We present high resolution (R = 100,000) L-band spectroscopy of 11 Herbig AeBe stars with circumstellar disks. The observations were obtained with the VLT/CRIRES to detect hot water and hydroxyl radical emission lines previously detected in disks around T Tauri stars. OH emission lines are detected towards 4 disks. The OH P4.5 (1+,1-) doublet is spectrally resolved as well as the velocity profile of each component of the doublet. Its characteristic double-peak profile demonstrates that the gas is in Keplerian rotation and points to an emitting region extending out to ~ 15-30 AU. The OH, emission correlates with disk geometry as it is mostly detected towards flaring disks. None of the Herbig stars analyzed here show evidence of hot water vapor at a sensitivity similar to that of the OH lines. The non-detection of hot water vapor emission indicates that the atmosphere of disks around Herbig AeBe stars are depleted of water molecules. Assuming LTE and optically thin emission we derive a lower limit to the OH/H2O column density ratio > 1 - 25 in contrast to T Tauri disks for which the column density ratio is 0.3 -- 0.4.

Accepted for publication in ApJ

References in corpus (15)

• Accretion Rates in Herbig Ae stars
• H2O and OH gas in the terrestrial planet-forming zones of protoplanetary disks
• High-Resolution Spectroscopy in Tr37: Gas Accretion Evolution in Evolved Dusty Disks
• Evolution of emission line activity in intermediate mass young stars
• Parameters of Herbig Ae/Be and Vega-type stars
• Accretion Disks around Young Stars: Lifetimes, Disk Locking and Variability
• Formation of Water in the Warm Atmospheres of Protoplanetary Disks
• Binarity as a key factor in protoplanetary disk evolution: Spitzer disk census of the eta Chamaeleontis cluster
• Detection of an inner gaseous component in a Herbig Be star accretion disk: Near- and mid-infrared spectro-interferometry and radiative transfer modeling of MWC 147
• Long-wavelength observations of debris discs around sun-like stars
• Planet formation around stars of various masses: Hot super-Earths
• Fundamental Vibrational Transition of CO during the Outburst of EX Lupi in 2008
• Spectral signatures of disk eccentricity in young binary systems: I. Circumprimary case
• Molecular hydrogen in the circumstellar environments of Herbig Ae/Be stars probed by FUSE
• An Inner Gaseous Disk around the Herbig Be Star MWC 147

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