Six-color photometry of stars. VIII. The colors of 409 stars of different spectral types

Photoelectric measures in six colors have been obtained for 171 stars in addition to the previous list of 238, making a total of 409 stars. Also the colors of 35 stars from the earlier list have been revised. The new colors determined with the Crossley reflector at the Lick Observatory have been reduced to the system of those with the reflectors at Mount Wilson. The mean colors for the different spectral types have been compared with those of the 0 stars as nearest to black-body standards. The Paschen and Balmer depressions in the continuum are measures of the hydrogen absorption, most conspicuous in A stars. Our observed Paschen effect agrees with that shown by Hall and Williams, and our Balmer effect is well correlated quantitatively with the measures of Barbier and Chalonge. Deviations from the law of interstellar absorption, previously noted in the case of Ol Orionis, are shown to be complicated by the possible presence of unseen companions of later spectral type.