Correlation Between the Regional Variations in Wavelength Dependence of Interstellar Extinction and Polarization

Abstract

The ratio of the amount of interstellar polarization in the yellow spectral region to that in the blue (or ultraviolet) is well correlated with the ratio of color excesses EV_I/EV_R. The maximum of polariza- tion is shifted toward longer wavelengths for the higher values of the ratio R of total to selective extinc- tion A formula is given for estimating R from the ratio of the amount of polarization in the yellow to that in the blue spectral region A pronounced wavelength dependence of position angles of polarization was found for several stars, confirming Gehrels' and Silvester's results Polarization not exceeding 0 0005 mag was found for the seventeen stars nearer than 10 pc observed with the 24-inch rotatable telescope of Siding Spring Observatory A large percentage of emission-line B-type stars show intrinsic polarization diminishing in the ultraviolet more sharply than does the interstellar polarizatio