Spectrophotometry of the white dwarfs

Multicolor spectrophotometry of 319 white dwarfs gives magnitudes measured at six wavelengths. The resultant colors permit study of a number of peculiarities of energy distributions, as revealed in color-color diagrams. The major results are presented in a table, which includes luminosities, as deduced from (G-R) colors, by a quadratic interpolation formula based on 66 recent parallaxes. All stars are classified on a new quantitative scheme which both gives a temperature and indicates the major features of atmospheric composition. The color-color diagrams are used to study the distortions of the energy distribution of individual stars. The parallaxes and colors show that the "cosmic dispersion" is near ±0.40 mag and corresponds to a small spread in mass, probably 0.10 - 0.15 M_sun;. Implications of some of these largely empirical findings for the current theoretical interpretation of white dwarfs are briefly discussed.