The Spectrum of RY SGR during Recovery from its 1993 Minimum
Abstract
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. (SECTION: Stars)
- Publication:
-
Publications of the Astronomical Society of the Pacific
- Pub Date:
- March 1995
- DOI:
- 10.1086/133546
- Bibcode:
- 1995PASP..107..244V
- Keywords:
-
- Absorption Spectra;
- Emission Spectra;
- Infrared Spectra;
- R Coronae Borealis Stars;
- Red Shift;
- Stellar Envelopes;
- Stellar Winds;
- Escape Velocity;
- Gas Flow;
- Radial Velocity;
- Spectrum Analysis;
- Astronomy;
- STARS: CHROMOSPHERES;
- STARS: ATMOSPHERES