Abundance Anomalies in the X-Ray Spectra of Planetary Nebulae NGC 7027 and BD +30°3639

Holly L. Maness, Grinnell College
Saeqa D. Vrtilek, Harvard-Smithsonian Center for Astrophysics
Joel H. Kastner, Rochester Institute of Technology
Noam Soker, Oranim, Tivon

© 2003 The American Astronomical Society.

We would like to thank our referee, Dr. R. Corradi for his thoughtful comments. H.M. was supported by the NSF REU program at SAO. S.D.V. was supported in part by NASA Grant NAG5-6711. J.H.K. acknowledges support for this research provided by NASA/CXO grants GO0–1067X and GO2-3009X to RIT. N.S. acknowledges support from the US-Israel Binational Science Foundation and the Israel Science Foundation.ISSN:1538-4365

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We revisit Chandra observations of the planetary nebulae NGC 7027 and BD +30◦3639 in order to address the question of abundance anomalies in the X-ray emitting gas. Enhanced abundances relative to solar of magnesium (Mg) for NGC 7027 and neon (Ne) for BD +30◦ 3639 are required to fit their X-ray spectra, whereas observations at optical and infrared wavelengths show depleted Mg and Ne in these systems. We attribute the enhancement of Mg in NGC 7027 in the X-ray, relative to the optical, to the depletion of Mg onto dust grains within the optical nebula. For BD +30◦ 3639, we speculate that the highly enhanced Ne comes from a WD companion, which accreted a fraction of the wind blown by the asymptotic giant branch progenitor, and went through a nova-like outburst which enriched the X-ray emitting gas with Ne (Refer to PDF file for exact formulas).