000002612 001__ 2612
000002612 005__ 20160701171708.0
000002612 037__ $$aASTROimport-769
000002612 100__ $$aKimeswenger, S.
000002612 245__ $$aSymmetry and Asymmetry in "born again" Planetary Nebulae
000002612 260__ $$c2007
000002612 520__ $$aWhile in the past spheroidicity was assumed, and still is used in modeling of most nebulae, we know now that only a small number of planetary nebulae (PNe) are really spherical or at least nearly round. Round planetary nebulae are the minority of objects. In case of those objects that underwent a very late helium flash (called VLTP or "born-again" PNe) it seems to be different. The first, hydrogen rich PN, is more or less round. The ejecta from the VLTP event is extremely asymmetrically. Angular momentum is mostly assumed to be the main reason for the asymmetry in PNe. Thus we have to find processes either changing their behavior within a few hundred to a few thousands of years or change their properties dramatically due to the variation of the abundance. They most likely have a strong link or dependency with the abundance of the ejecta. 
000002612 700__ $$a Zijlstra, A. A.
000002612 700__ $$a van Hoof, P. A. M.
000002612 700__ $$a Hajduk, M.
000002612 700__ $$a Lechner, M. F. M.
000002612 700__ $$a van de Steene, G. C.
000002612 700__ $$a Gesicki, K.
000002612 773__ $$c17$$pAsymmetrical Planetary Nebulae IV$$y2007
000002612 85642 $$ahttp://esoads.eso.org/abs/2007apn4.confE..17K
000002612 905__ $$apublished in
000002612 980__ $$aNONREF