Elemental Abundance Analyses with DAO Spectrograms. XXXVI. The Hot Metallic Line Stars Theta Leonis and Omicron Pegasi

摘要

This series contains high-quality LTE elemental abundance analyses of sharp-lined and moderately rotating normal and peculiar Main Sequence Band B, A, and F stars. Their compositions were determined for comparison with analyses of somewhat similar stars and with theoretical predictions. Here we provide new and improved elemental abundances analyses for the well-studied hot metallic line stars theta Leonis and o Pegasi to better understand their relationship with other A stars. The analyses, which employ Kurucz's ATLAS9 model atmospheres and WIDTH9 codes and high signal-to-noise ratio (S/N) spectrograms obtained with Reticon and CCD detectors, are consistent with our previous analyses based upon coadded photographic plates. The spectral synthesis program STELLAR is used with the fluxes, the H gamma profiles, and the spectra to provide better estimates of the effective temperature, surface gravity, and metallicity. The agreement of the results for two species of the same element are usually improved. The errors have been slightly reduced compared to those of their previous analyses using DAO spectrograms. Abundances of additional elements have been determined. The very high S/N (>= 500) spectra of o Peg (used previously for the stellar atlas of Gulliver et al.) were critical to finding the weakest lines and to defining the profiles of all lines. High-quality spectrograms of additional regions especially those longward of H beta can be used to obtain some missing elemental abundances in both stars.