Document Type

Article

Publication Date

3-30-2011

Publication Title

The Astrophysical Journal

Volume

732

Issue

2

Publisher

The American Astronomical Society

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 linespreviously detected in disks around T Tauri stars. OH emission lines are detected toward four disks. The OH 2Π3/2 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 toward 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 atmospheres 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.

Comments

This manuscript has been published in the Astrophysical Journal. Please find the published version here (note that a subscription may be necessary to access this version):

http://iopscience.iop.org/0004-637X/732/2/106

The American Astronomical Society holds the copyright in this article

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