J/A+AS/116/95 J/A+AS/116/95 Magellanic Clouds PNe line intensities P Leisy M Dennefeld Astron. Astrophys. Suppl. Ser. 116 95 1996 1996A&AS..116...95L Magellanic Clouds Planetary nebulae Spectroscopy galaxies: abundances galaxies: evolution Magellanic Clouds planetary nebulae: general We present optical and ultraviolet spectroscopic observations of planetary nebulae (PNe) in the Large (LMC) and the Small Magellanic Clouds (SMC). For the visible spectra with highest S/N, line intensities have been measured to a few tenths of a percent of H_{beta}_. UV spectra are used for the determination of carbon abundances. This paper discusses the CNO cycle and its implications. We show that the CN or ON cycles are more effective with lower initial metallicities and are always complete for typeI nebulae. The latter cannot easily be distinguished from non-type I PNe on the basis of N or He abundance alone, as continuity exists in all of the standard diagrams. From the study of the C abundances, we deduce that the 3rd dredge-up is occurring in all PNe: its efficiency too is higher with lower initial metallicities, offering an easy explanation for the higher number of carbon stars found in metal-deficient galaxies. It is shown that this dredged-up carbon is sometimes transformed into nitrogen by Hot-Bottom Burning, but in a few objects only and not even in all the typeI PNe, which therefore do not form a homogeneous class.

Name Planetary nebulae name --- Lambda Wavelength --- Ident Line identification --- Flambda Extinction curve value for Lambda --- l_Fobs Limit flag on Fobs --- Fobs Observed line intensity number=1 scale F(Hbeta)=100 --- u_Fobs Uncertainty flag on Fobs --- l_Fcor Limit flag on Fcor --- Fcor Corrected line intensity number=1 scale F(Hbeta)=100 --- u_Fcor Uncertainty flag on Fcor --- Name Planetary nebula name --- l_Fb Limit flag on Fb --- Fb Flux Hbeta (10-16 erg/cm2/s-1) 10-16mW/m2 e_Fb Hbeta uncertainty % Exp1 IUE exposure number (first number) --- Exp2 IUE exposure number (second number) --- Exp3 IUE exposure number (third number) --- Ne Electronic density cm-3 T(OIII) [OIII] electronic temperature K T(NII) [NII] electronic temperature K Copt Logarithmic extinction constant --- e_Copt rms uncertainty on Copt --- Patricia Bauer CDS 1996Jan09P. Leisy <Leisy@iap.fr> J_A+AS_116_95.xml