Interstellar CA II lines in SMC stars

Interstellar Ca ii lines of reddened early-type stars in the SMC were observed. In addition to the component from the Milky Way, strong lines were detected at radial velocities corresponding to gas in the SMC. The interstellar Ca n lines are abnormally strong, given the small color excesses of the stars and the low metallicity of the SMC gas, which suggests that the grains contain a much smaller fraction of the interstellar calcium than they do in our galaxy. The radial velocities do not conflict with the two-galaxy model for the SMC of Matthewson and Ford (1983) if the higher-velocity system is behind the lower-velocity system.