On stellar statistics

Abstract

In this paper a method is proposed for treating the fundamental equation of stellar statistics which will take into account the known cloud structure of the interstellar absorbing matter. The method is based on the determination and the interpretation of the fluctuations in the numbers of stars, N(m), per unit solid angle, and brighter than a given apparent magnitude, m, in the various parts of the sky. The marked dependence of these fluctuations on the galactic latitude confirms their relation to the interstellar clouds. Theoretical formulae are derived for the dispersions to be expected in N(m) as a function of the galactic latitude on certain idealized distributions of stars and clouds. The results of star counts tabulated by van Rhijn and by Baker and Kiefer are analyzed in terms of these formulae, and a theoretical prediction based on them is verified. The analysis discloses the importance of taking into account the dispersion in the transparencies of the interstellar clouds as a factor in these considerations.