PI: Bruce Hrivnak, Valparaiso University, Bruce.Hrivnak@valpo.edu
Address: Department of Physics and Astronomy, 1610 Campus Drive East, Valparaiso, IN 46383, USA
CoI: Ken Hinkle, NOAO
Title: Testing the Binary Hypothesis for Bipolar Proto-Planetery Nebulae
Abstract: We propose to test the popular but observationally unsupported hypothesis that the bipolar shapes of planetary nebulae (PNe) arise from the interaction of a binary companion. The observing targets are three edge-on proto-PNe (PPNe) in which the central star is obscured in visible light by an optically-thick torus but in which the central star can be seen in the near-infrared. We would obtain high-precision radial velocity observations of the central stars to search for radial velocity variations. This radial velocity study will provide a stringent test of the popular binary hypothesis as the mechanism to produce this torus that then collimates the outflow to produce the bipolar nebulae. A positive result would support the binary hypothesis and open the way to determine the exact shaping mechanism. A null result would rule out the presence of a close binary and also specifically the idea of post-AGB binaries (~30% of all AGB stars) as predecessors of bipolar PPNe and the close binary central stars of PNe as their progeny. These observations would extend the time baseline of radial velocity observations approved for 2010A.
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