The Ultraviolet Emission Spectra of Planetary Nebulae
نویسندگان
چکیده
منابع مشابه
Emission lines of O III in the optical and ultraviolet spectra of planetary nebulae
Recent R-matrix calculations of electron impact excitation rates in O iii are used to calculate electron temperature and density-dependent emission line ratios R1 = I(4363 Å)/I(4960 Å + 5007 Å), R2 = I(1661 Å + 1667 Å)/I(4960 Å + 5007 Å) and R3 = I(2322 Å)/I(1661 Å + 1667 Å), for a range of electron temperatures (7500 ≤ Te ≤ 30 000 K) and densities (104 ≤ Ne ≤ 107 cm−3) applicable to gaseous ne...
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Stars at the top of the asymptotic giant branch (AGB) can exhibit maser emission from molecules like SiO, H2O and OH. These masers appear in general stratified in the envelope, with the SiO masers close to the central star and the OH masers farther out in the envelope. As the star evolves to the planetary nebula (PN) phase, mass-loss stops and ionization of the envelope begins, making the maser...
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This paper continues our study of the behaviour of near infrared helium recombination lines in planetary nebula. We find that the 1.7007μm 4D–3P HeI line is a good measure of the HeI recombination rate, since it varies smoothly with the effective temperature of the central star. We were unable to reproduce the observed data using detailed photoionisation models at both low and high effective te...
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Electron impact excitation rates in Cl III, recently determined with the R-matrix code, are used to calculate electron temperature (T(e)) and density (N(e)) emission line ratios involving both the nebular (5517.7, 5537.9 A) and auroral (8433.9, 8480.9, 8500.0 A) transitions. A comparison of these results with observational data for a sample of planetary nebulae, obtained with the Hamilton Echel...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1968
ISSN: 0074-1809
DOI: 10.1017/s007418090002043x