Magnesium abundances in planetary nebulae and interstellar absorption of MG II 2800 A
نویسندگان
چکیده
منابع مشابه
Planetary nebulae abundances and stellar evolution II *
Context. In recent years midand far infrared spectra of planetary nebulae have been analysed and lead to more accurate abundances. It may be expected that these better abundances lead to a better understanding of the evolution of these objects. Aims. The observed abundances in planetary nebulae are compared to those predicted by the models of Karakas (2003, Thesis, Monash Univ. Melbourne) in or...
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Emission-line abundances have been uncertain for more than a decade due to unexplained discrepancies in the relative intensities of the forbidden lines and weak permitted recombination lines in planetary nebulae (PNe) and H II regions. The observed intensities of forbidden and recombination lines originating from the same parent ion differ from their theoretical values by factors of more than a...
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The mid-infrared spectrum of the rather circular planetary nebula NGC 2792 taken with the Spitzer Space Telescope is presented. This spectrum is combined with the ultraviolet IUE spectrum and with the spectrum in the visual wavelength region to obtain a complete, extinction corrected, spectrum. The chemical composition of the nebula is then calculated in two ways. First by directly calculating ...
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A summary is given of planetary nebulae abundances from ISO measurements. It is shown that these nebulae show abundance gradients (with galactocentric distance), which in the case of neon, argon, sulfur and oxygen (with four exceptions) are the same as HII regions and early type star abundance gradients. The abundance of these elements predicted from these gradients at the distance of the Sun f...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 1988
ISSN: 0035-8711,1365-2966
DOI: 10.1093/mnras/231.4.1025