Extragalactic symbiotic systems I. IUE observations of LMC 1, N 67, SMC 3, and S 154

We present UV spectra of 4 symbiotic systems in the Magellanic Clouds obtained with IUE. Relative CNO abundances of the nebular material are given, and it is shown that the nature of the cool companion giant is reflected in the nebular chemistry. Estimates for the temperature and luminosity of the hot radiation source are given. Because the distances to these objects are well known, we can derive unbiased luminosities of the hot components in these symbiotic systems. Unlike the galactic symbiotics, our four objects are confined to a small region in the Hertzsprung-Russell diagram, though, this might be due to a selection effect, since our sample is not statistically significant. Our main aim is to show the potential of future UV observations for deriving accurate temperatures and luminosities of the hot components in symbiotics, and for determining CNO abundances in extragalactic red giants.