K 648, the planetary nebula in the globular cluster M 15.

Abstract

IUE observations of the planetary nebula K648 in the globular cluster M15 have been obtained, and the first determinations of the C abundance in the nebular envelope have been made. Improved measurements of fluxes in the optical nebular emission lines and in forbidden N II 6583 have been obtained. Semiforbidden C III 1908 and C II 2326 are strong nebular emission features and C IV 1549 is a broad stellar absorption feature. The nebular shell abundances include: (C/H) = +0.05; (N/H) = -1.5; (O/H) = -1.25; and (He/H) = -1.5. The large C abundance indicates enrichment by material which has been involved in He burning. The C IV absorption is interpreted as being due to a P Cygni feature. The stellar mass loss rate is about 2 x 10 to the -10th solar masses/yr. The ionized hydrogen mass is 0.011 solar mass. The central star has 3000 solar luminosities for an adopted effective temperature of 38,000 + or - 4000 K.