THE HOT R-CORONAE-BOREALIS STAR DY CENTAURI - NEBULAR AND PHOTOSPHERIC LINES

High resolution spectra in the red region of the hot R CrB star DY Cen show the following characteristics: a strong absorption line spectrum dominated by lines of C II, N II, and Ne I, inverse P-Cygni type prof iles of some C II and He I lines, and emission lines of [N II], [S II] , and [O I]. The star also seems to possess an expanding chromosphere or stellar wind region. The forbidden lines indicate the presence of a low excitation nebula with an electron temperature of less-than-or-eq ual-to 1 0 000 K and an electron density of 450 cm-3. The presence of low excitation nebulae may be a common property of the hotter R CrB st ars.