Near-infrared observations of interstellar polarization

Interstellar linear polarization has been observed at three wavelengths between 1 and 2.2 microns for seven stars. It is found that the polarization tends to decrease much less rapidly to wavelengths longward of that at which maximum polarization occurs than predicted by Serkowski's (1968) empirical relation. The observations appear to be consistent with a model in which the polarization is produced by a mixture of graphite and silicates rather than by pure silicates.