X-ray sources in molecular clouds

Abstract

Models are calculated for the structure and infrared line emission from a dense interstellar gas cloud containing a compact X ray source. For constant gas pressure models, the resulting structure consists of nested spherical shells containing, respectively, coronal gas at a temperature exceeding 1,000,000 K, an H II region with a temperature around 10,000 K, an H I region with T of about 8000 K, and finally an H2 region with T below 5000 K. Scaling laws are given for the locations of the transitions. Approximately 10 percent of the X ray luminosity absorbed in the H2 region is converted into IR emission lines that may be observable. Line ratios are predicted.