The Chemical Composition of Planetary Nebulae
نویسندگان
چکیده
منابع مشابه
Chemical abundances of planetary nebulae towards the
In this paper we report new observations and derive chemical abundances for a sample of 26 planetary nebulae (PN) located in the anticenter direction. Most of these nebulae are far away objects, located at Galactocentric distances greater than about 8 kpc, so that they are particularly useful for the determination of the radial gradients at large distances from the galactic center. A comparison...
متن کاملThe chemical evolution of planetary nebulae
We report millimeter line observations of CO, 13CO, SiO, SiC2, CN, HCN, HNC, HCO+, CS, and HC3N to study the chemistry in planetary nebulae (PNe) withmassive envelopes of molecular gas. The sample observed consists of representative objects at different stages of development in order to investigate evolutionary effects: the proto-PNe CRL 2688 and CRL 618, the young PN NGC 7027, and the evolved ...
متن کاملPlanetary Nebulae and the Chemical Evolution of the Magellanic Clouds
The determination of accurate chemical abundances of planetary nebulae (PN) in different galaxies allows us to obtain important constraints of chemical evolution models for these systems. We have a long term program to derive abundances in the galaxies of the Local Group, particularly the Large and Small Magellanic Clouds. In this work, we present our new results on these objects and discuss th...
متن کاملChemical abundances of planetary nebulae towards the galactic anticenter
In this paper we report new observations and derive chemical abundances for a sample of 26 planetary nebulae (PN) located in the anticenter direction. Most of these nebulae are far away objects, located at galactocentric distances greater than about 8 kpc, so that they are particularly useful for the determination of the radial gradients at large distances from the galactic center. A comparison...
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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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1968
ISSN: 0074-1809
DOI: 10.1017/s0074180900020611