High-resolution spectroscopy of QY Sge: an obscured RV Tauri variable?

Abstract

The first high-resolution optical spectra of QY Sge are presented and discussed. Menzies & Whitelock, on the basis of photometry and low-resolution spectra, suggested that this G0I supergiant was obscured by dust and seen only by scattered light from a circumstellar reflection nebula. The new spectra confirm and extend this picture. Photospheric lines are unusually broad indicating scattering of photons from dust in the stellar wind. The presence of very broad, NaD emission lines is confirmed. Sharp emission lines from low levels of abundant neutral metal atoms are reported for the first time. An abundance analysis of photospheric lines shows that the stellar atmosphere is of approximately solar composition but with highly condensable (e.g. Sc and Ti) elements depleted by factors of 5-10.