Deciphering the 3-D Orion Nebula-II: A low-ionization region of multiple velocity components southwest of Theta1OriC confounds interpretation of low velocity resolution studies of temperature, density, and abundance

Abstract

We establish that there are two velocity systems along lines-of-sight that contribute to the emission-line spectrum of the the brightest parts of the Orion Nebula. These overlie the Orion-S embedded molecular cloud southwest of the dominant ionizing star (Theta1OriC). Examination of 10x10" samples of high spectral resolution emission-line spectra of this region reveals it to be of low ionization, with velocities and ionization different from the central part of the Nebula. These properties jeopardize earlier determinations of abundance and physical conditions since they indicate that this region is much more complex than has been assumed in analyzing earlier spectroscopic studies and argue for use of very high spectral resolution or known simple regions in future studies.

9 pages, 2 figures

References in corpus (7)

• The Gould's Belt Distances Survey (GOBELINS) II. Distances and structure towards the Orion Molecular Clouds
• On the abundance discrepancy problem in HII regions
• Properties of the ionized gas in HH202. II: Results from echelle spectrophotometry with UVES
• The three dimensional dynamic structure of the inner Orion Nebula
• Deviations from He I Case B Recombination Theory and Extinction Corrections in the Orion Nebula
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Cited by in corpus (6)

• Photoionized Herbig-Haro objects in the Orion Nebula through deep high-spectral resolution spectroscopy II: HH204
• Multiline observations of hydrogen, helium, and carbon radio-recombination lines toward Orion A: A detailed dynamical study and direct determination of physical conditions
• Backscattering and Line Broadening in Orion
• Deciphering the 3-D Orion Nebula-III: Structure on the NE boundary of the Orion-S Embedded Molecular Cloud
• Large Scale Wind Driven Structures in the Orion Nebula
• Deciphering the 3-D Orion Nebula-IV: The HH~269 flow emerges from the Orion-S Embedded Molecular Cloud