Accession Number : AD0783983

Title :   Radio Recombination Line Observation of the CII Region NGC2023,


Personal Author(s) : Knapp,Gillian R. ; Brown,Robert L. ; Kuiper,Tom B. H.

Report Date : 1974

Pagination or Media Count : 36

Abstract : The reflection nebula NGC 2023 has been observed at four frequencies in a study of its carbon recombination line emission. The observations show the recombination line region to be about 2 pc in diameter, with an average electron density of approximately 0.2/cc and electron temperature of approximately 20K. The electron density increases exponentially near the B1.5 star HD37903, the illuminating star of NGC 2023. The most reasonable interpretation of the observational results is that the carbon emission lines arise in a cold CII region surrounding HD37903. The coexistence of the CII region with a region of enhanced CO emission suggests that the CO in NGC 2023 may be excited by electron collisions. (Author)

Descriptors :   *Nebulae, *Emission spectra, *Extraterrestrial radio waves, *Carbon, Reflection, Carbon monoxide, Recombination reactions, Line spectra, Stars, Electron density

Subject Categories : Astrophysics

Distribution Statement : APPROVED FOR PUBLIC RELEASE