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)
Astrophys.J. 589 (2003) 439-443
RIT – Main Campus