AAS 207th Meeting, 8-12 January 2006
Session 182 Stellar Winds, Circumstellar Matter, and Activity
Poster, Thursday, 9:20am-4:00pm, January 12, 2006, Exhibit Hall

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[182.24] NeVII: Powerful Wind Diagnostics For Very Hot Stars

J.E. Herald (The Johns Hopkins University)

We have recently identified a strong P Cygni feature (\lambda 973)in the far-UV spectra of some very hot (Teff > 85,000 K) central stars of planetary nebulae (CSPN) as originating from Ne~VII. Using stellar atmosphere models, we reproduce this feature as it is observed in hydrogen-deficient CSPN, as well as in PG~1159 objects. The discovery of neon diagnostic features in CSPN spectra is important because an overabundance of this element is indicative of processed material that has been dredged up to the surface from the interior region as predicted in the ``born-again'' scenario, an explanation of hydrogen-deficient CSPN. We explore the potential of this strong feature as well as weaker neon features as diagnostics in stellar atmosphere analyses for extremely hot post-ABG objects (where other diagnostics are scarce).

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