Spectropolarimetry of the 3.4 m Band in the Quintuplet

We present spectropolarimetry of the 3.4?m solid hydrocarbon absorption feature arising in the ISM toward the Quintuplet member GCS3-II, permitting for the first time a comparison of the hydrocarbon and silicate polarizations in the same line of sight. The hydrocarbon band is not measurably polarized, strengthening our previous conclusion that the silicates and carbonaceous grains form distinct populations.