Understanding the Eskimo
Roberto Mendez



The Eskimo (NGC 2392) and its central star have long been known to have some remarkable peculiarities: high nebular expansion velocity, too high He II Zanstra temperature, anomalously strong N lines and weak C lines in the central star spectrum. Using new, high signal-to-noise CFHT ESPaDOnS visual spectrograms, and archive IUE and FUSE UV spectrograms, together with state-of-the-art non-LTE model atmospheres, we have obtained reliable He, C, N, O photospheric abundance determinations in the central star of NGC 2392. We compare these results with photospheric abundances in two "more normal" central stars (NGC 6826 and IC 4593), which bracket NGC 2392 in surface temperature, and we also compare with the corresponding nebular abundances, taken from other studies. Armed with this information, we offer an interpretation that can potentially explain all the peculiarities of the Eskimo.