Radiative shock dynamics. I. The Lyman continuum.
Abstract
The paper investigates coupled non-LTE radiative transfer and nonlinear hydrodynamics by considering a shock propagating outward through an atmosphere of pure hydrogen in which the hydrogen atoms have one bound level and a continuum. Self-consistent numerical solutions are obtained for the nonlinear hydrodynamic equations, the transfer equation for Lyman continuum radiation, and the time-dependent population equation for atoms with one bound level plus continuum. Results are discussed for a piston-driven shock propagating through a static atmosphere in radiative and statistical equilibrium, with attention given to the formation of the ionization front, the ionization contour, and the radiation intensity at the Lyman edge. The structure of the temperature spike developed by the shock is compared for the three cases of adiabatic, collisional, and radiating shocks. It is shown that the escape of recombination radiation narrows the temperature spike at small optical depth and that low postshock densities in the upper atmosphere reduce the three-body recombination rate and produce a large plateau of nearly constant ionization behind the shock.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 1976
- DOI:
- 10.1086/154304
- Bibcode:
- 1976ApJ...205..499K
- Keywords:
-
- Hydrodynamics;
- Hydrogen Atoms;
- Lyman Spectra;
- Radiative Transfer;
- Shock Wave Propagation;
- Stellar Atmospheres;
- Atmospheric Models;
- Continuous Radiation;
- Finite Difference Theory;
- Gas Ionization;
- Hydrodynamic Equations;
- Temperature Profiles;
- Thermodynamic Equilibrium;
- Astrophysics