Analysis and Models of Photoionized Structures Seen in [ITAL]Hubble Space Telescope[/ITAL] Images of NGC 7635

Autor: Brian D. Moore, J. Jeff Hester, Donald K. Walter, Paul A. Scowen
Rok vydání: 2002
Předmět:
Zdroj: The Astronomical Journal. 124:3305-3312
ISSN: 1538-3881
0004-6256
DOI: 10.1086/344597
Popis: 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.
Databáze: OpenAIRE