PLANETARY-NEBULAE IN THE GLOBULAR-CLUSTERS PAL-6 AND NGC-6441

Jacoby & Fullton (1998, in preparation) recently surveyed the Galactic globular cluster system for planetary nebulae and identified excellen t candidates in the disk clusters Pal 6 and NGC 6441. Velocities, abun dances, and central star properties for these two nebulae are derived. There is a 0.5% probability that the nebula in Pal 6 is a chance supe rposition of a Galactic bulge nebula. Membership for the nebula in NGC 6441, though, is extremely likely based on common velocity, extinctio n, and proximity to the cluster center. The number of nebulae now know n in globular clusters (4) represents a 3.1 sigma departure from the n umber expected (16) based on the theoretical stellar death rate (Renzi ni & Buzzoni 1986) and the depth of the survey, Possible rationales fo r this apparent discrepancy are discussed, In particular, the small nu mber of observed PN in clusters can be explained by imposing the requi rement that cluster PN form from binary progenitors, Statistically, a correlation exists between the presence of PN and the presence of x-ra y sources in clusters, suggesting that PN are more likely to be found when the frequency of interacting binaries in a cluster is high. Oxyge n abundances for these two PN, plus Ps1 in M15, suggest that the [O/Fe ] ratios in cluster stars are not uniform from cluster to cluster. Val ues range from -0.7 (NGC 6441) to +0.8 (M15), as compared to +0.5 typi cally measured in low metallicity field stars. (C) 1997 American Astro nomical Society.