PI: Orsola De Marco, Macquarie University, email@example.com
Address: Physics Department, North Ryde, Sydney, NSW 2109, Australia
CoI: Todd Hillwig, Valparaiso University
CoI: George Jacoby, NOAO
CoI: Maxwell Moe, Harvard University
CoI: David Frew, Macquarie University
Title: Do most planetary nebulae come from binaries?
Abstract: There is evidence suggesting that the vast majority of planetary nebulae (PNe) harbor close binary central stars. If so, PNe would be a binary interaction phenomenon. If this were the case, there would be repercussion in our understanding of galactic enrichment, nebular shaping mechanisms, and the relationship between central stars of PN and other post-common envelope and strong interaction binary classes. In this proposal we seek to test this hypothesis by determining the central star binary fraction. So far we know that 15-20% of central stars of PN are in binaries with periods <a few days, but the technique used to find them is insensitive at longer periods. We have recently carried out an I-band excess survey at the NOAO 2.1 m telescope, from which we determined a binary fraction much larger than predicted by the traditional scenario that explains PNe as the inevitable product of intermediate mass evolution. However, the limited sample size and poor sensitivity of the I-band to late companions, limited the statistical relevance of our result. We therefore propose to cash in on our experience and carry out the survey in the J band using WIYN+WHIRC and OPTIC. The target list is drawn from the newly compiled 2-kpc volume limited sample, a terrific asset in PN research.
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