We reexamine the spectroscopic underpinnings of recent suggestions that [O I] and [Fe II] lines from the Orion H II region are produced in gas where the iron-carrying grains have been destroyed and the electron density is surprisingly high. Our new observations show that previous detections of [O I] 5577 were dominated by telluric emission. Our limits are consistent with a moderate density (≈ 104 cm-3) photoionized gas. We show that a previously proposed model of the Orion H II region reproduces the observed [O I] and [Fe II] spectrum. These lines are fully consistent with formation in a dusty region of moderate density.
Digital Object Identifier (DOI)
Baldwin, J. A.; Crotts, A.; Dufour, R. J.; Ferland, Gary J.; Heathcote, S.; Hester, J. J.; Korista, K. T.; Martin, P. G.; O'Dell, C. R.; Rubin, R. H.; Tielens, A. G. G. M.; Verner, D. A.; Walter, D. K.; and Wen, Z., "Physical Conditions in Low-Ionization Regions of the Orion Nebula" (1996). Physics and Astronomy Faculty Publications. 147.