Variability of Ultraviolet Emission in the Carbon Star TX PISCIUM
Johnson, Hollis R.; Baumert, John H.; Querci, Francois; Querci, Monique
United States, France
Abstract
Multiple low-resolution IUE observations of the cool carbon star TX Psc (NO; C6,2) permit an analysis of the variations in strength of the strongest emission lines - the Mg II line at 2800 Å, the C II line at 2330 Å, and certain Fe II lines. In the present sample of nine spectra, the integrated flux of the Mg II line varies by at least a factor of 8, while that of the C II line varies by at least a factor of 5. The continuous flux in the best observed range from 2800 to 3200 Å does not vary noticeably. Possible mechanisms for the production of these variable emission lines are reviewed.