1995PASP..107..244V

A spectrum of the RCB star RY Sge in the red and near-IR was obtained during its recovery from a deep minimum. The spectrum shows numerous weak emission lines blueshifted by 20 km/sec relative to the photosphere of the star. In addition to the emission line spectrum, strong, blueshifted Na I D lines are seen in absorption at a velocity of -200 km/sec. an analysis of these lines shows that the column density of Na I in this fast-moving cloud is 2.5 X 10^13 cm^-2 and that the Na I/K I ratio is substantially enhanced above the solar ratio. The inverse P Cygni profiles of the weak sharp lines are consistent with a picture in which outward moving gas may be interacting with a layer above it to create a weak shock capable of ionizing metals but no C I.