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.

ApJ Letters, in press

References in corpus (5)

• Spectral Mapping Reconstruction of Extended Sources
• Submillimeter arcsecond-resolution mapping of the highly collimated protostellar jet HH 211
• SWAS Observations of Water in Molecular Outflows
• A far-infrared molecular and atomic line survey of the Orion KL region
• Star formation in the vicinity of the IC 348 cluster

Cited by in corpus (18)

• Formation of Water in the Warm Atmospheres of Protoplanetary Disks
• 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
• 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
• Proper motions of collimated jets from intermediate-mass protostars in the Carina Nebula
• ATOMIUM: Probing the inner wind of evolved O-rich stars with new, highly excited H${}_2$O and OH lines
• OH mid-infrared emission as a diagnostic of H${}_2$O UV photodissociation. III. Application to planet-forming disks
• 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
• 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
• Autodetachment of diatomic carbon anions from long-lived high-rotation quartet states
• Formation of phosphorus monoxide (PO) in the interstellar medium: insights from quantum-chemical and kinetic calculations