Abstract
In their study on C/N/O abundances in red giants, planetary nebulae, novae and symbiotic stars Nussbaumer, Schild, Schmid and Vogel (1988: Astron.Astrophys.198, 179) pointed out that among symbiotic stars HM Sge is quite exceptional, in that its C/N/O abundance ratios rather resemble those of novae and not of symbiotic stars.In 1975 HM Sge brightened within a few months by at least 4m. The object has been observed in radio, visual, X-ray, and since 1978 with IUE. Here we show the changing level of activity in the UV. Figure 1 gives the FES (IUE fine error sensor) counts, representing an integrated flux at visual wavelengths. This flux shows a general decline with a secondary maximum in 1982. – Our mFES is at variance with the visual magnitude estimates given by Munari and Whitelock (1989: Mon.Not.Roy.astr.Soc. 237, 45p). They report high brightness up to at least the end of 1984.
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