Disk and outflow signatures in Orion-KL: The power of high-resolution thermal infrared spectroscopy

Abstract

We used the CRIRES spectrograph on the VLT to study the ro-vibrational 12CO/13CO, the Pfund beta and H2 emission between 4.59 and 4.72mu wavelengths toward the BN object, the disk candidate source n, and a proposed dust density enhancement IRC3. We detected CO absorption and emission features toward all three targets. Toward the BN object, the data partly confirm the results obtained more than 25 years ago by Scoville et al., however, we also identify several new features. While the blue-shifted absorption is likely due to outflowing gas, toward the BN object we detect CO in emission extending in diameter to ~3300AU. Although at the observational spectral resolution limit, the 13CO line width of that feature increases with energy levels, consistent with a disk origin. If one attributes the extended CO emission also to a disk origin, its extent is consistent with other massive disk candidates in the literature. For source n, we also find the blue-shifted CO absorption likely from an outflow. However, it also exhibits a narrower range of redshifted CO absorption and adjacent weak CO emission, consistent with infalling motions. We do not spatially resolve the emission for source n. For both sources we conduct a Boltzmann analysis of the 13CO absorption features and find temperatures between 100 and 160K, and H2 column densities of the order a few times 10^23cm^-2. The observational signatures from IRC3 are very different with only weak absorption against a much weaker continuum source. However, the CO emission is extended and shows wedge-like position velocity signatures consistent with jet-entrainment of molecular gas, potentially associated with the Orion-KL outflow system. We also present and discuss the Pfund beta and H2 emission in the region.

12 pages, 15 pages, accepted for A&A, you find a high-resolution copy at http://www.mpia-hd.mpg.de/homes/beuther/papers.html

References in corpus (10)

• The UKIRT Infrared Deep Sky Survey (UKIDSS)
• Dust Masses, PAH Abundances, and Starlight Intensities in the SINGS Galaxy Sample
• The distance to the Orion Nebula
• Radiation-Hydrodynamic Simulations of Collapse and Fragmentation in Massive Protostellar Cores
• The c2d Spitzer spectroscopic survey of ices around low-mass young stellar objects II: CO2
• Infall of gas as the formation mechanism of stars up to 20 times more massive than the Sun
• Tracing the inner edge of the disk around HD 100546 with Ro-vibrational CO Emission Lines
• Hubble Space Telescope Survey of Interstellar ^12CO/^13CO in the Solar Neighborhood
• Identifying the outflow driving sources in Orion-KL
• Kinematics of a hot massive accretion disk candidate

Cited by in corpus (11)

• A Multi-Epoch Study of the Radio Continuum Emission of Orion Source I: Constraints on the Disk Evolution of a Massive YSO and the Dynamical History of Orion BN/KL
• On the simultaneous evolution of massive protostars and their host cores
• On the stability of radiation-pressure-dominated cavities
• Protostellar Outflows and Radiative Feedback from Massive Stars
• Herschel observations of extra-ordinary sources: Detection of Hydrogen Fluoride in absorption towards Orion~KL
• The near-infrared reflected spectrum of source I in Orion-KL
• Herschel observations of EXtra-Ordinary Sources (HEXOS): Observations of H2O and its isotopologues towards Orion KL
• The Orion Protostellar Explosion and Runaway Stars Revisited: Stellar Masses, Disk Retention, and an Outflow from BN
• A study of dynamical processes in the Orion KL region using ALMA-- Probing molecular outflow and inflow
• The mid-infrared molecular inventory towards Orion IRc2
• High spectral resolution observations toward Orion BN at 6 $\mu$m: no evidence for hot water