Radiative opacity of stellar matter.

Abstract

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Radiative opacity of stellar matter. Zirin, Harold Abstract A detailed calculation has been made of absorption coefficients and opacities of the hot, dense gas inside a star. The basic assumption made is that the potential field surrounding a nucleus in the stellar gas is that due to the nucleus and to a uniform cloud of electrons surrounding it, up to the boundary of a neutral sphere. Outside this ion sphere the potential is zero. I have found by a variational technique the wave functions describing the motion of the electrons in this potential field, both in bound and free states. If we then assume that the electrons are distributed in energy according t6 the Fermi Dirac statistics, we may determine the potential field due to the electrons moving with these wave functions. The resulting potential field almost exactly duplicates the assumed potential, especially in very hot gases, therefore justifying our approximation. We have in computing the self-consistent potential developed the exchange potential for a non-degenerate free electron gas along the theory of Dirac. This turns out to be appreciable even in hot gases. I have determined the absorption coefficients for free-free and bound-free transitions in various elements of astrophysical interest, using the wave function of electrons in the assumed potential corresponding to a given temperature and density. With these absorption coefficients it is possible to compute the opacity of any astrophysical mixture, under a wide variety of temperatures and pressures. The opacity turns out to be much smaller than computed by Miss Harrison, because of the effect of pressure ionization. As a result of this, the radiative temperature gradient at the center of the sun must be much smaller, and the convective core much larger, than found by some other workers using Miss Harrison's tables. The Rand Corporation, Santa Monica, Ca 1sf. Publication: The Astronomical Journal Pub Date: March 1953 DOI: 10.1086/106820 Bibcode: 1953AJ.....58...50Z full text sources ADS |