The Chemical Composition of Red Giants, AGB Stars and Planetary Nebulae
نویسندگان
چکیده
منابع مشابه
Planetary nebulae as probes of the chemical impact of AGB stars Letizia Stanghellini
Planetary nebulae (PN) represent the evolutionary fate of the asymptotic giant branch (AGB) stellar envelopes, thus are ideally suited to study the chemical impact of AGB stars. Stellar evolution predict elemental enrichment through the AGB evolution, and convective dredge-up episodes allow the products of stellar evolution to reach the stellar outer layers. Planetary nebulae are probes of thes...
متن کاملPlanetary nebulae as probes of the chemical impact of AGB stars
Planetary nebulae (PN) represent the evolutionary fate of the asymptotic giant branch (AGB) stellar envelopes, thus are ideally suited to study the chemical impact of AGB stars. Stellar evolution predict elemental enrichment through the AGB evolution, and convective dredge-up episodes allow the products of stellar evolution to reach the stellar outer layers. Planetary nebulae are probes of thes...
متن کاملMagnetic fields in planetary nebulae and post-AGB nebulae
Magnetic fields are an important but largely unknown ingredient of planetary nebulae. They have been detected in oxygen-rich AGB and post-AGB stars, and may play a role in the shaping of their nebulae. Here we present SCUBA sub-millimeter polarimetric observations of four bipolar planetary nebulae and post-AGB stars, including two oxygen-rich and two carbon-rich nebulae, to determine the geomet...
متن کاملStellar Evolution from AGB to Planetary Nebulae
Planetary nebulae are formed by an interacting winds process where the remnant of the AGB wind is compressed and accelerated by a later-developed fast wind from the central star. One-dimensional dynamical models have successfully explained the multi-shell (bubble, shell, crown, haloes) structures and the kinematics of planetary nebulae. However, the origin of the diverse asymmetric morphology o...
متن کاملThe effect of turbulent pressure on the red giants and AGB stars
The expressions for the turbulent pressure, equation of state and thermodynamic quantities taking account of turbulent pressure are derived in the framework of the mixing-length theory of convection. The numerical computations indicate that the turbulent pressure in the region close to the surface of a red giant or anAGB star can reach a value of 30-40 percent of the total pressure. A compariso...
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ژورنال
عنوان ژورنال: Proceedings of the International Astronomical Union
سال: 2006
ISSN: 1743-9213,1743-9221
DOI: 10.1017/s174392130600305x