Ultraviolet and optical observations of AG Draconis

Extended variability of the symbiotic star AG Draconis

“…2a). In Figure 2a (SWP 15710) a P Cygni profile is evident in the >..1238.8 component, we obtained ~v-200 km s-1 which is in agreement with Viotti et al ( 1983Viotti et al ( , 1984 and Lutz et al ( 1987). Note the unique, peculiar double profile of the >..1242.8 component in SWP 15710 ( Fig.…”

“…Following Flower & Nussbaumer (197 5), we derived electron densities from the 0 IV] density-dependent line ratios /(>..1404.81)/ /(>..1401.16) and /(>..1407 .39 )/ /(>..1401.16). These line intensity ratios imply a density in the range 10 10 ::;; n.::;; 10 u cm-3 • This estimate is higher than most other electron density estimates, n.-10 10 cm-3 (Viotti et al 1983;Lutz et al 1987).…”

“…This is a false inverse P Cygni profile due to the presence of interstellar Mg II absorption features (cf. Viotti et al 1983;Lutz et al 1987). Because the Mg II line fluxes were obtained by different cameras at different times, uncertainties in the line intensities could be high -20%-30%.…”

“…The binary system of AG Draconis consists of a hot star and a cool K giant of a controversial spectral class. Kenyon & Webbink ( 1984) consider it to be of K3 III type, whereas Lutz et al ( 1987) assign a luminosity class III and K1 type to the primary, and Allen (see Kenyon 1986) assumes it to be ofK1 ± 1 III type. Finally, Kenyon & Femandez-Castro (1987) found the cool star to be earlier than K4 III from infrared data.…”

“…N v AA1238, 1242, C IV AA1548, 1550, He II Al640) and weak intersystem emission lines (e.g. 0 IV] AA1397-1407, N m] AA1747-1753, Si m] A1892, C m] AA1907, 1909) (Lutz & Lutz 1981;Altamore et al 1982;Viotti et al 1982Viotti et al , 1983Viotti et al , 1984Lutz et al 1987).…”