Constant-Flux Convective Model Atmospheres.

Abstract

view Abstract Citations (55) References (9) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Constant-Flux Convective Model Atmospheres. Mihalas, Dimitri Abstract Modtl atmospheres have been constructed using the mixing4ength theory to describe the convective transport of energy. The condition of flux constancy is enforced allowing for the simultaneous energy transport by convection and non-gray radiative processes, using a modification of the temperature-correction procedure proposed by Avrett and Krook. The modified equations allow for the convection terms explicitly and, in a more general sense, show that the Avrett-Krook procedure provides a powerful formalism for enfordng the condition of flux constancy in the presence of non-radiative terms. A grid of models has been constructed on the range 0.5 < 0 < 0.7 and 2 < log g < 444 assuming (1/H) = land (t/H) = 2. It is found that the presence of convection produces substantial changes in the structure of the atmosphere at depth, while the overlying radiative layer is virtually unchanged. The emergent flux distribution in the continuum and line profiles are examined with the view of obtaining a criterion for distinguishing convective models from radiative, and the two assumed mixing lengths from one another It is found that only the emergent flux in the rocket or satellite ultraviolet provides such a measure in the sense that the ultraviolet fluxes are appreciably smaller for the convective models. The profiles of HT computed for the convective models differ from those for the radiative models by less than 1 or 2 per cent in all but a few cases, and thus do not provide a clear criterion for establishing convection On the other hand, it is found that in the convective models lines from certain neutral metals may be strengthened relative to the ionic lines, compared to the radiative models. A more detailed solution of the statistical equilibrium equations should be carried out to confirm this conclusion. Publication: The Astrophysical Journal Pub Date: February 1965 DOI: 10.1086/148145 Bibcode: 1965ApJ...141..564M full text sources ADS | Related Materials (1) Erratum: 1970ApJ...161..375M