|Author||Maness, Holly L. ♦ Vrtilek, Saeqa D. ♦ Kastner, Joel H. ♦ Soker, Noam|
|Subject Domain (in DDC)||Computer science, information & general works ♦ Data processing & computer science|
|Subject Keyword||X-ray Emitting Gas ♦ Infrared Wavelength ♦ Optical Nebula ♦ White Dwarf Companion ♦ General Planetary Nebula ♦ Chandra Observation ♦ Asymptotic Giant Branch Progenitor ♦ Subject Heading ♦ Enhanced Ne ♦ Planetary Nebula Ngc ♦ Abundance Anomaly ♦ Planetary Nebula ♦ Novalike Outburst ♦ Dust Grain ♦ Ism On-line Material ♦ Whereas Observation ♦ X-ray Spectrum ♦ Enhanced Abundance|
|Abstract||We revisit Chandra observations of planetary nebulae NGC 7027 and BD +303639 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 +303639 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 +303639, we speculate that the highly enhanced Ne comes from a white dwarf companion, which accreted a fraction of the wind blown by the asymptotic giant branch progenitor and went through a novalike outburst that enriched the X-ray–emitting gas with Ne. Subject headings: planetary nebulae: general — planetary nebulae: individual (BD+303639, NGC 7027) — stars: winds, outflows — X-rays: ISM On-line material: color figures 1.|
|Educational Role||Student ♦ Teacher|
|Age Range||above 22 year|
|Education Level||UG and PG ♦ Career/Technical Study|
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