• What is HEXOS?
  • Team Members
• Observational Program
  • Main Goals
  • Observations & Sub Programs
    • Orion KL HIFI/PACS
    • Orion S HIFI/PACS
    • Orion Bar Program
    • Sgr B2 (N) HIFI/PACS
    • Sgr B2 (M) HIFI/PACS
    • Orion Water Mapping
    • Polarization
    • Searching for Deep Molecules
    • Searching for Large Molecules
• Publications & Presentations
• Detected Far-Infrared Lines
• Data Reduction Resources
• HEXOS Wiki
• Get HEXOS Data

Orion Bar—HIFI/PACS Line Survey

The Orion Bar provides an excellent opportunity to study the interaction between star formation and interstellar gas in general, and photodissociation region (PDR) physics in particular. PDR’s are regions exposed to stellar ultraviolet radiation (6 eV < hν < 13.6 eV) which alter the chemistry, thermal balance, and hence emission of the exposed layers. This back-reaction of the newly formed stars thus effects the further evolution of the molecular clouds and plays an important role in the overall evolution of the ISM in galaxies. With its close proximity and well characterized edge-on geometry, the Orion Bar is the prime laboratory to test the predictions of chemical/thermal PDR models. We plan complete scans of the HIFI bands (using frequency switching) and also PACS range spectroscopy in SED red and blue wavelength ranges. This will be supplemented by numerous deep HIFI intergrations and a few small maps of key species. Marco Spaans, Juergen Stutzki, and Christine Joblin are the co-coordinators of this subprogram, with Jose Cernicharo the coordinator for PACS scans.

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