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).
Department, Program, or Center
Chester F. Carlson Center for Imaging Science (COS)
Holly L. Maness et al 2003 ApJ 589 439 https://doi.org/10.1086/374414
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