Axisymmetric Dust-Shells in Planetary Nebulae
نویسندگان
چکیده
منابع مشابه
Dust Extinction in Compact Planetary Nebulae
The effects of dust extinction on the departure from axi-symmetry in the morphology of planetary nebulae (PNs) are investigated through a comparison of the radio free-free emission and hydrogen recombination line images. The dust exctinction maps of five compact PNs are derived using high-resolution (∼0. 1) Hα and radio images maps of the HST and VLA. These extinction maps are then analyzed by ...
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We have observed a sample of eleven PNe using the PHT-C100 camera on ISO, obtaining maps at 60 and 100 m. The PHT-32 mapping mode was used, resulting in images of the PNe and nearby sky background. A preliminary reduction of the data has conrmed that the radial extent of the cool dust in general is similar to the optical nebula. Two of the PN in our sample have been clearly resolved at 60 and 1...
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We have performed a statistical analysis using broad band IRAS data on about 500 planetary nebulae with the aim of characterizing their dust content. Our approach is different from previous studies in that it uses an extensive grid of photoionization models to test the methods for deriving the dust temperature, the dust-to-gas mass ratio and the average grain size. In addition, we use only dist...
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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 will review our mid-infrared and HST imaging surveys of the circumstellar dust shells of proto-planetary nebulae. While optical imaging indirectly probes the dust distribution via dust-scattered starlight, midIR imaging directly maps the distribution of warm dust grains. Both imaging surveys revealed preferencially axisymmetric nature of PPN dust shells, suggesting that axisymmetry in planet...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1993
ISSN: 0074-1809
DOI: 10.1017/s0074180900170901