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C. Sanchez Contreras (California Institute of Technology), R. Sahai (Jet Propulsion Laboratory / Caltech), A. Gil de Paz (Carnegie Obs.), R. W. Goodrich (W.M. Keck Obs.)
The process that triggers and drives jet-like winds beyond the Asymptotic Giant Branch (AGB), which is reponsible for the shaping of planetary and protoplanetary nebulae (PNe and PPNe), remains very poorly known. We present echelle long-slit optical spectra (obtained with ESI on Keck II) of a sample of young PPNe/PNe candidates selected from our on-going optical+NIR imaging and CO mapping surveys (with HST and the Owens Valley Radio Observatory, OVRO, millimeter array, respectively). Most of the observed sources show broad H alpha wings (~500-2000 kms-1) that indicate that the jet-sculpting of the AGB envelope has already started and is most likely currently active. In many cases, fast, post-AGB winds are also revealed by P-Cygni profiles close to the central star, providing a unique way of directly studying "pristine" post-AGB ejections (before they are altered by the interaction with the AGB envelope). These observations provide important information on the spatio-kinematic structure and physical conditions of the extended, shocked lobes and the pristine post-AGB winds (probed by the blue-shifted absorption features) as well as the connection between both components in a large sample of young PPNe and PNe. From the detailed analysis of these data (and data from our HST and OVRO surveys) we aim at improving our understanding of post-AGB winds and their interaction with the AGB envelopes.
The author(s) of this abstract have provided an email address for comments about the abstract: sanchez@astro.caltech.edu
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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.