Electronic computations of astrophysical interest.

Abstract

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Electronic computations of astrophysical interest. Olson, Edward C. ; Stewart, Jon A. ; Wrubel, Marshal H. ; Schroeder, Leon W. Abstract Using the IBM Type 65o magnetic drum calculator astronomers at Indiana University have programmed several problems of interest in stellar interiors and stellar atmospheres. Stellar interiors. Olson programmed the computation of Rosseland mean opacities so that the relative abundances of the elements can be varied. Dr. G. Keller generously provided the basic data that were used in the Keller-Meyerott computations. The purpose of this investigation was to permit the compuhtion of opacities for a variety of mixtures of interest in stellar evolution. The computations at present are limited to the values of the temperature and density parameters originally used by Keller and Meyerott. A single mean opacity can be obtained in 2~4' minutes of machine computation. This program can be run on any IBM 65o and will be made available on request. Stewart used Olson's calculations and recent revisions by Fowler et al. of nuclear cross sections, to find more accurate interpolation formulae for ic and E than have previously been used in the integration of stellar models. These formulae may be easily programmed for electronic computers although they are rather complicated for hand computation. Formulae of this type were used by Sears in the solar models described in another paper at these meetings. Stellar atmospheres. A program by Wrubel permits the calculation of theoretical line profiles and curves of growth for idealized models. Milne-Eddington profiles for varying ratios of line absorption to line scattering were computed using this program. It can be easily adapted to other models. This program will also be made available on request. Last year, Heiser reported on some work done at Indiana, in which solar magnesium line profiles were predicted by calculations involving Hubenet's model atmospheres. Heiser took into account the detailed variation of ionization, damping, etc. with depth. Schroeder has now shown, using Wrubel's program, that Heiser's results can be duplicated in terms of the MilneEddington model if the appropriate parameters are taken as constant and equal to their values at optical depth o.So. Schroeder has further extended this work to similar lines of Procyon, using a model atmosphere kindly provided in advance of publication by Dr. F. Edmonds. This work is being supported in part by the National Science Foundation. Goethe Link Observatory, Indiana University, Bloomington, Ind. and Oklahoma A. & M. College, Stillwater, Okla. Publication: The Astronomical Journal Pub Date: February 1958 DOI: 10.1086/107687 Bibcode: 1958AJ.....63...52O full text sources ADS |