The Empirical Mass-Luminosity Relation.

Abstract

After a brief historical introduction the problem is subdivided into two main parts. The first, on the temperature scale and bolometric corrections, is treated in the preceding article. The second problem, the derivation of the empirical mass-luminosity refation, is treated in three sections in this article: (i) the visual binaries, (2) some selected spectroscopic binaries, and (3) Trumpler's massive stars in clusters. An at- tempt has been made to obtain the most accurate observational data for all quantities entering into the discussion, including magnitudes and spectral types. Tables 1 and 7 giye the visual binaries used at present. Table 5 shows the derived quantities for the stars of Table 1, and Table 6 shows the quantities of theoretical interest for the stars of Table 5 for which the accuracy is sufficiently great. Visual binaries in the same class as those of Table 1, but for which the data are still incomplete, are collected in Table 8. The problem of the spectroscopic binaries is only partly treated in this paper. Only some representative objects are discussed; they are found in Table 12. Theoretical values of the ellipticity and reflection constants are used in the discussion of the ob- servations. Trumpler's massive stars are discussed in Table 13. In all three sections the results of the preceding article have been used. The data are shown graphically in Figures 1 and 2.