Interstellar lines toward the Cepheus OB2 association

We present an analysis of the interstellar-line spectra of four stars in the Cepheus OB2 association. The cloud has strong lines of both Ca+ and Ca0, and electron-number densities are determined directly from the N (Ca0)/N (Ca+) ratio. The depletions of Ca and Ti are found to be less than in typical diffuse interstellar clouds, and we suggest that these metals have been released from the grains in the cloud--a suggestion supported by the observed shorter wavelength of maximum interstellar polarization toward the cloud.Copernicus observations of lambda Cep, one of the program stars, reveal the present of large column densities of both molecular and atomic hydrogen commensurate with the observation of strong lines of CH, CH+, and CN