A New Method for Observational Testing of the Planetary Nebulae Nuclei Evolution
نویسندگان
چکیده
منابع مشابه
The 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 ...
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We present high resolution spectrophotomet-ric data for a sample of 34 planetary nebulae with [WC] spectral type central stars (WRPNe) in our Galaxy. The observed objects cover a wide range in stellar characteristics: early and late [WC] type stars, as well as weak-emission line stars (WELS). Physical conditions in the nebulae (electron density and temperatures) have been obtained from various ...
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This paper discusses the location of a sample of planetary nebulae on the HR diagram. We determine the internal velocity fields of 14 planetary nebulae from high-resolution echelle spectroscopy, with the help of photoionization models. The mass averaged velocity is shown to be a robust, simple parameter describing the outflow. The expansion velocity and radius are used to define the dynamical a...
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Expansion velocities (Vexp) of different ions and line widths at the base of the lines are measured and analyzed for 24 PNe with [WC]-type nuclei (WRPNe), 9 PNe ionized by WELS (WLPNe) and 14 ordinary PNe. A comparative study of the kinematical behavior of the sample clearly demonstrates that WRPNe have in average 40-45% larger Vexp, and possibly more turbulence than WLPNe and ordinary PNe. WLP...
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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...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1989
ISSN: 0074-1809
DOI: 10.1017/s0074180900139105