منابع مشابه
Turbulent planetary nebulae around [ WC ] – type stars ⋆
Through a high-resolution spectroscopic survey, we analyze the velocity field of 16 planetary nebulae with [WC]or wels-type nuclei in comparison with 8 nebulae having other central star types. We found spectral evidence for finite turbulent velocities in [WC]-type planetary nebulae superimposed on an essentially constant expansion velocity pattern. The nebulae around O-type stars show no eviden...
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 ...
متن کاملIntracluster Planetary Nebulae
We review the progress of research on intracluster planetary nebulae (IPN). In the past five years, hundreds of IPN candidates have been detected in the Virgo and Fornax galaxy clusters and searches are also underway in poorer galaxy groups. From the observations to date, and applying the known properties of extragalactic planetary nebulae, the intracluster light in Virgo and Fornax: 1) is sign...
متن کاملHydrogen-poor planetary nebulae
Five planetary nebulae are known to show hydrogen-poor material near the central star. In the case of A58, this gas was ejected following a late thermal pulse similar to Sakurai. In this paper I will review these five objects. One of them, IRAS 18333−2357, may not be a true PN. I will show that there is a strong case for a relation to the [WC] stars and their relatives, the weak emission-line s...
متن کاملEvolution of Planetary Nebulae I. An improved synthetic model
We present a new synthetic model to follow the evolution of a planetary nebula (PN) and its central star, starting from the onset of AGB phase up to the white dwarf cooling sequence. The model suitably combines various analytical prescriptions to account for different (but inter-related) aspects of planetary nebulae, such as: the dynamical evolution of the primary shell and surrounding ejecta, ...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 1993
ISSN: 0074-1809
DOI: 10.1017/s0074180900170585