||When Asymmetric Cosmic Bubbles Betray a Difficult Marriage: the Study of Binary Central Stars of Planetary Nebulae
||447, Evolution of Compact Binaries
||Boffin, H. M. J.; Miszalski, B.
||Planetary Nebulae represent a powerful window into the evolution of
low-intermediate mass stars that have undergone extensive mass-loss. The
nebula manifests itself in an extremely wide variety of shapes, but exactly
how the mass lost is shaped into such a diverse range of morphologies is still
highly uncertain despite over thirty years of vigorous debate. Binaries have
long been thought to offer a solution to this vexing problem. Now, thanks to
recent surveys and improved observing strategies, it appears clearly that a
binary channel, in particular common-envelope (CE) evolution, is responsible
for a large fraction of planetary nebulae. Moreover, as planetary nebulae are
just “fresh out of the oven” compared to other post-CE systems, they provide
invaluable contributions to the study of common-envelope evolution and to the
formation of jets in binary systems. Our studies have also started to identify
strong links between binarity and morphology, including a high proportion of
bipolar nebulae and rings of low ionisation filaments resembling SN 1987A.
Equally important are the newly found binary CSPN with intermediate periods,
which appear linked to chemically peculiar stars whose composition was
modified by binary evolution. Their study may also reveal much information on
mass and angular momentum transfer processes in binary stars. Here we show
examples of four PNe for which we have discovered their binary nature,
including the discovery of a rare case of a barium-rich cool central star.