Interpretation of Fraunhofer-line profiles
Abstract
From the experimentally determined cross-sections of the Na atom for collisions of the second kind it is shown that the hypothesis of true absorption is probably not applicable to the formation of Fraunhofer lines in the solar photosphere. Using atomic transition probabilities for radiative excitation and ionization, values of the source functions and the ratio of the line to the continuous absorption coefficients are derived in terms of kinetic, excitation and ionization temperatures. The functional dependence of these quantities on the optical depth is such as to permit a numerical integration of the exact equation of transfer, and the method of effecting this integration is outlined
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- 1955
- DOI:
- 10.1093/mnras/115.3.256
- Bibcode:
- 1955MNRAS.115..256P