The structure and dynamics of H II regions

Abstract

view Abstract Citations (11) References (38) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The structure and dynamics of H II regions Welter, G. L. Abstract The early evolution of H II regions, through the first few times 100,000 years, is investigated under conditions of enhanced central density and increasing cluster luminosity. It is found that a D-type ionization front can overtake the precursor shock under conditions of a fairly steep density gradient such as may exist just beyond a stellar dust cocoon, or as new stars turn on within the H II region. The shock is converted into a strong, outward moving pressure pulse as it is ionized. The evolutionary effects of different recombination rates within the ionization front and different cooling rates within the shocked layer are investigated and found to be small. Possible modifications which the presence of dust or stellar winds could produce are briefly considered. Publication: The Astrophysical Journal Pub Date: September 1980 DOI: 10.1086/158256 Bibcode: 1980ApJ...240..514W Keywords: Astronomical Models; Evolution (Development); Gas Ionization; H Ii Regions; Nebulae; Cosmic Dust; Density Distribution; Line Spectra; Shock Fronts; Astrophysics full text sources ADS |