Morphologies of the Nebulae around "born-again" Central Stars of Planetary Nebulae

Kimeswenger, S.; Zijlstra, A. A.; van Hoof, P. A. M.; Hajduk, M.; Herwig, F.; Lechner, M. F. M.; Eyres, S. P. S.; Van de Steene, G. C.

Morphologies of the Nebulae around "born-again" Central Stars of Planetary Nebulae

Authors

Description

While in the past spherodicity was assumed, and still is used in modeling of most nebulae, we know now that only a small number of planetary nebulae (PNe) are really spherical or at least nearly round. Round planetary nebulae are the minority of objects. In the case of those objects that underwent a very late helium flash (called VLTP objects or ``born-again'' PNe) it seems to be different. The first, hydrogen-rich PN, is more or less round. The ejecta from the VLTP event, in contrast, are extremely asymmetrical.
to appear in the proceedings of HYDEF07, Tuebingen 2007