NOAO >   Observing Info >   Approved Programs >   2001B-0164

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Proposal Information for 2001B-0164


PI: Jennifer Birriel, Carleton College, jbirriel@carleton.edu
Address: One North College St., Northfield, MN 55057, UAS

Title: A Search for Raman Scattered He II in Selected Bipolar Planetary Nebulae

Abstract: Spectroscopic similarities between bipolar, proto-planetary nebulae and symbiotic stars have lead many researchers to speculate on possible evolutionary links between the two types of objects (Lee & Park 1999). The binarity of symbiotics is well-established while that of bipolar proto-planetary nebulae remains a matter of debate. In 1997 Pequignot et al. observed a Raman scattered He II line at 4851 Ain the optical spectrum of the young planetary nebulae NGC 7027. This unusual planetary nebula appears to have two central stars and has been discussed as a possible post-symbiotic system (Gurzadyan, 1997). With the exception NGC 7027, Raman scattering is found to occur only in symbiotic stars. Several of the symbiotics which exhibit Raman scattering display bipolar structure similar to many planetary nebulae. I propose a search for the Raman scattered He II line at 4851 Ain the spectra of several bipolar planetary nebulae and symbiotic stars as a means of investigating a potential evolutionary link between symbiotic stars and planetary nebulae.


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