9915(  1) - 04/04/03 10:14  - [  1]

    PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS   ST ScI Use Only
                                                       ID:      9915
                                                       Version: 1
                                                       Check-in Date: 04-Apr-2003
                                                                      10:13:56

1.Proposal Title:
Stellar wind interactions around binary stars: models for planetary nebulae
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2. Proposal For  3. Cycle
AR               11
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4. Investigators
                                                                                     Contact?
    PI: Roger Chevalier                   The University of Virginia
   CoI: Dr. John Blondin                  North Carolina State University               N
   CoI: Dr. Noam Soker                    Technion-Israel Institute of Technology       N

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5. Abstract

HST observations of proto-planetary nebulae and planetary nebulae suggest that
bipolar structure in these objects is due to a fast collimated wind expanding in the
more spherically symmetric slow wind of an AGB (asymptotic giant branch) star. A
possible mechanism for creating the collimated wind involves the flow from a
companion star (to the AGB star) with a disk around it due to accretion. Although
scenarios can be developed for the interaction of the collimated wind from the
orbiting star with the AGB star wind, 3-dimensional hydrodynamic models are needed
to clarify the outcome. We propose to undertake such calculations, using the VH-1
code. Both parameter studies and models aimed at individual objects will be
calculated. Special attention will be given to hydrodynamic instabilities in 3
dimensions. Model images will be produced assuming emission either by scattered
light from a central source or from gas heated by photoionization. Comparison with
HST images should show whether the circumstellar features expected in binary systems
are present and, if so, what binary parameters are needed.
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                                                9915(  1) - 04/04/03 10:14  - [  2]

            Summary Form for Proposal  9915

  Item                         Used in this proposal
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  Proposal Category            AR
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