Accession Number : AD0856416

Title :   Spectral Line Profiles and Radiative Transfer.

Descriptive Note : Technical rept. 1 Jun 63-1 Sep 64,

Corporate Author : JOINT INST FOR LAB ASTROPHYSICS BOULDER CO

Personal Author(s) : Jefferies, J. R. ; Hummer, D. G. ; Oxenius, J. ; Avrett, E. H. ; Bainbridge, Janet

Report Date : JUL 1969

Pagination or Media Count : 378

Abstract : The first five sections of this report deal with the problem of spectral line formation with particular reference to astrophysics. The Introduction (Section I) reviews the framework of the problem and discusses the relevance of the succeeding Sections to one another. Section II considers aspects of the problem involved in computing the intensity of radiation in and emerging from an atmosphere of specified structure when local thermodynamic equilibrium cannot be assumed a priori. In Section III we present an analysis of the solar Na D lines. This proceeds from a quite general basis and, so far as we know, is the first analysis of its kind to have been made. Section IV contains a discussion of the inversion of Fredholm's integral equation of the first kind--specifically for the form encountered in the limb-darkening problem. In Section V we present a treatment of a special case occurring in the theory of the transfer equation in two level atom. In section VI is given a tabulation of the Voigt function, whose importance in the theory of the line absorption coefficient is well known. The final section, Section VII, presents a study and a tabulation of the absorption coefficient of the H(-) ion for free-free transitions. This ion has, of course, long been recognized as providing the major part of the continuous opacity of the sun and other similar stars. (Author)

Descriptors :   (*LINE SPECTRA, ASTROPHYSICS), HYDROGEN, IONS, INTENSITY, INTEGRAL EQUATIONS, FUNCTIONS(MATHEMATICS), ABSORPTION, SCATTERING, REPORTS, TRANSPORT PROPERTIES, SOLAR SPECTRUM, THERMAL RADIATION, EXCITATION, SUBROUTINES, SODIUM.

Subject Categories : Astrophysics
      Atomic and Molecular Physics and Spectroscopy

Distribution Statement : APPROVED FOR PUBLIC RELEASE