Elemental abundance analyses with DAO spectrograms - XIV. The double-lined spectroscopic binary 112 Herculis

We have extensively studied both components of the double-lined spectroscopic binary 112 Her using photographic region high-resolution Reticon spectra obtained at the Dominion Astrophysical Observatory. The orbital radial-velocity curves for both stars have been used to derive more accurate orbital elements and a mass ratio of 1.98. We have employed both fine-analysis and spectrum-synthesis techniques. 112 Her A is an HgMn star with large He and Mg deficiencies, and a large iron overabundance. Its chemical composition is similar to that of HR7664, another hot HgMn star with a large Fe overabundance, but its Mn abundance falls below the envelope of abundance versus temperature defined by most class members. 112 Her B exhibits a pattern of derived abundances similar to the Am and partially similar to the cool rapidly oscillating Ap stars. Its photospheric elemental abundances are very similar to those of HR4072 B and chi Lup B, which also have HgMn-star primaries.