Recent Optical and UV Emission Line Variability in the Symbiotic Star CH Cyg

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Session 45 -- CVs/Symbiotic Stars
Display presentation, Wednesday, 1, 1994, 9:20-6:30

[45.08] Recent Optical and UV Emission Line Variability in the Symbiotic Star CH Cyg

J. P. Aufdenberg, K. D. Gordon, B. W. Bopp (U. of Toledo)

The symbiotic star CH Cygni has shown abrupt changes in the emission profiles of H$\alpha$, He I 5875 \AA, and the Na I D-lines. CCD echelle spectra obtained at Ritter Observatory between Jun.\ 30 and Oct.\ 4 1993 show a single strong emission line at H$\alpha$, with an essentially constant profile. From Oct.\ 8 through Dec.\ 12 1993 additional ``emission'' components formed and faded on a time scale of days on the blue wing of H$\alpha$ at velocities from -45 to -275 km/s. Whether these components are truly emission lines or windows in an absorbing curtain is unclear. The blue wing and continuum, out to at least -500 km/s, were also variable while the red wing and continuum remained unchanged. On Oct.\ 8 the FWHM of the He I 5875 \AA\ emission line doubled and a P-Cyg absorption component abruptly formed at -200 km/s. The Na I D-lines were then seen in emission with P-Cyg structure developing over the next week. The width and strength of these P-Cyg absorption features were variable through Dec.\ 12. In addition an IUE high dispersion spectrum was obtained on Nov.\ 25 1993 showing similar P-Cyg structure in the Mg II h\&k doublet and the Fe II UV multiplets. These UV emission lines show an increase in flux while the UV continuum indicates an increasingly optically thick shell phase when compared with spectra from May 1993. The optical and UV spectra will be presented and discussed.

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