Chemical abundances of the planetary nebula IC 4634 and its central star

We have measured the spectral line intensities of the metal-poor planetary nebula IC 4634. Using a photoionization model calculation, we try to fit th e optical and UV region spectra, i.e., Hamilton echelle and IUE observation s. From direct images, one expects complicated density variations, but the model predicts a range in densities that may be smaller than actually exist . We find N-epsilon similar to 5000 cm(-3). In spite of the geometrical com plexity of the S-shaped double-lobed structure, the simple photoionization model with a spherical symmetry can fit most emission lines fairly well. Th e derived chemical composition has been compared with previous estimates an d also with the Sun. The metallicity in IC 4634 appears to be lower than in the Sun or the average planetary nebula. The most likely temperature of th e central ionizing source of IC 4634 appears to be similar to 55,000 K. We find a central star mass of similar to 0.55 M. from comparison with theoret ical evolutionary tracks.