Discovery of superthermal hydroxyl (OH) in the HH211 outflow

Abstract

We present a 5-37 micron infrared spectrum obtained with the Spitzer Space Telescope toward the southeastern lobe of the young protostellar outflow HH211. The spectrum shows an extraordinary sequence of OH emission lines arising in highly excited rotational levels up to an energy E/k~28200K above the ground level. This is, to our knowledge, by far the highest rotational excitation of OH observed outside Earth. The spectrum also contains several pure rotational transitions of H2O (v=0), H2 (v=0) S(0) to S(7), HD (v=0) R(3) to R(6), and atomic fine-structure lines of [Fe II], [Si II], [Ne II], [S I], and [Cl I]. The origin of the highly excited OH emission is most likely the photodissociation of H2O by the UV radiation generated in the terminal outflow shock of HH211.

arXiv commentApJ Letters, in press

References in corpus (15)

• The Infrared Array Camera (IRAC) for the Spitzer Space Telescope
• The Spitzer Space Telescope Mission
• Dust Grain Size Distributions and Extinction in the Milky Way, LMC, and SMC
• The Infrared Spectrograph on the Spitzer Space Telescope
• Thermal Desorption of Water-Ice in the Interstellar Medium
• Spectral Mapping Reconstruction of Extended Sources
• Molecular dynamics study of photodissociation of water in crystalline and amorphous ice
• Enhanced OH in C-type shock waves in molecular clouds
• Submillimeter arcsecond-resolution mapping of the highly collimated protostellar jet HH 211
• A spectral line survey of Orion KL in the bands 486-492 and 541-577 GHz with the Odin satellite II. Data analysis
• Molecular outflows in the young open cluster IC348
• A far-infrared molecular and atomic line survey of the Orion KL region
• SWAS Observations of Water in Molecular Outflows
• Star formation in the vicinity of the IC 348 cluster
• The near-infrared excitation of the HH211 protostellar outflow

Cited by in corpus (35)

• Interstellar water chemistry: from laboratory to observations
• Molecular excitation in the Interstellar Medium: recent advances in collisional, radiative and chemical processes
• Interstellar Hydrides
• Organic Molecules and Water in the Inner Disks of T Tauri Stars
• Emission Lines from the Gas Disk around TW Hydra and the Origin of the Inner Hole
• Formation of Water in the Warm Atmospheres of Protoplanetary Disks
• The Spitzer View of Low-Metallicity Star Formation: III. Fine Structure Lines, Aromatic Features, and Molecules
• Spitzer Spectroscopy of the Transition Object TW Hya
• Water in star-forming regions with Herschel: highly excited molecular emission from the NGC 1333 IRAS 4B outflow
• Ex Lupi from Quiescence to Outburst: Exploring the LTE Approach in Modelling Blended H2O and OH Mid-Infrared Emission
• OH emission from warm and dense gas in the Orion Bar PDR
• ALMA spectral line and imaging survey of a low and a high mass-loss rate AGB star between 335 and 362 GHz
• Waves on the surface of the Orion molecular cloud
• OH mid-infrared emission as a diagnostic of H${}_2$O UV photodissociation. I. Model and application to the HH 211 shock
• Discovery of Extremely High Velocity "Molecular Bullets" in the HH 80-81 High-Mass Star-Forming Region
• Spitzer spectral line mapping of the HH211 outflow
• JWST Observations of Young protoStars (JOYS): overview of program and early results
• JWST Observations of Young protoStars (JOYS). HH 211: the textbook case of a protostellar jet and outflow
• c2d Spitzer IRS spectra of embedded low-mass young stars: gas-phase emission lines
• Proper motions of collimated jets from intermediate-mass protostars in the Carina Nebula
• OH mid-infrared emission as a diagnostic of H${}_2$O UV photodissociation. III. Application to planet-forming disks
• ATOMIUM: Probing the inner wind of evolved O-rich stars with new, highly excited H${}_2$O and OH lines
• The circumestellar disk of the B0 protostar powering the HH 80-81 radio jet
• The feedback of atomic jets from embedded protostars in NGC 1333
• OH mid-infrared emission as a diagnostic of H${}_2$O UV photodissociation. II. Application to interstellar PDRs
• Quantum study of reaction O(3P) + H2(v,j) $\to$ OH + H: OH formation in strongly UV-irradiated gas
• Detection of highly excited OH towards AGB stars: A new probe of shocked gas in the extended atmospheres
• Herschel spectral-line mapping of the HH211 protostellar system
• Feedback of molecular outflows from protostars in NGC 1333, revealed by Herschel and Spitzer spectro-imaging observations
• Enhancing reactivity of SiO${}^{+}$ ions by controlled excitation to extreme rotational states
• A rich molecular chemistry in the gas of the IC 348 star cluster of the Perseus Molecular Cloud
• Challenging shock models with SOFIA OH observations in the high-mass star-forming region Cepheus A
• Autodetachment of diatomic carbon anions from long-lived high-rotation quartet states
• Effects of Reagent Rotation and Vibration on H + OH (v,j) $\to$ O + H2
• Formation of phosphorus monoxide (PO) in the interstellar medium: insights from quantum-chemical and kinetic calculations