Analysis and Models of Photoionized Structures Seen in Hubble Space Telescope Images of NGC 7635

We present the analysis of photoionized structures seen in Hubble Space Telescope Wide Field Planetary Camera 2 images of NGC 7635 and the surrounding H II region S162. We exploit the high spatial resolution images to make a census of the total ionizing flux from the O6.5 IIIf star BD +60°2522. We also construct detailed models of two structures with a photoionization code, reproducing the line emission seen in spatial profiles extracted directly from the images. We demonstrate that the density distribution of the models produces deviations in the spectrally derived elemental abundances at a level exceeding typical observational errors. Our results also show a large discrepancy between the star's effective temperature used for our best-fit models (34,320 K) and that expected based on its spectral type (>40,000 K) from a hot-star calibration taken from the literature. We suggest that this is due to the use of plane-parallel stellar atmospheres in constructing that calibration. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute (STScI), which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS 5-26555.