Local Density Variations in Planetary Nebulae
نویسندگان
چکیده
منابع مشابه
Planetary Nebulae Surveys Beyond the Local Group
Distant planetary nebulae (PNe) are used to measure distances through the PN luminosity function, as kinematic tracers in determining the mass distribution in elliptical galaxies, and most recently, for measuring the kinematics of the diffuse stellar population in galaxy clusters. This article reviews the photometric and spectroscopic survey techniques that have been used to detect PNe beyond t...
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The Local Group (LG) represents the best environment to study in detail the PN population in a large number of morphological types of galaxies. The closeness of the LG galaxies allows to investigate the faintest side of the PN luminosity function and to detect PNe also in the less luminous galaxies, the dwarf galaxies, where a small number of them is expected. A review of the results of the mos...
متن کاملPlanetary Nebulae
Planetary nebulae (PNe) can be used to trace intermediate and old stellar populations in galaxies and the intracluster medium out to approximately 20 Mpc. PNe can be easily identified with narrow-band surveys, and their chemical abundances and radial velocities can be measured with multi-slit or multi-fiber spectrographs. We briefly review what has been accomplished to date, and include tables ...
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We have determined fluorine abundances from the [F II] λ4789 and [F IV] λ4060 nebular emission lines for a sample of planetary nebulae (PNe). Our results show that fluorine is generally overabundant in PNe, thus providing new evidence for the synthesis of fluorine in asymptotic giant branch (AGB) stars. [F/O] is found to be positively correlated with the C/O abundance ratio, in agreement with t...
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Standard stellar evolution theory is inconsistent with the observed isotopic carbon ratio, C/C, in evolved stars. This theory is also inconsistent with the He/H abundance ratios observed in Galactic H II regions, when combined with chemical evolution theory. These discrepancies have been attributed to an extra, non-standard mixing which further processes material during the RGB and should lower...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1958
ISSN: 0074-1809
DOI: 10.1017/s0074180900226855