منابع مشابه
The post-AGB evolution of AGB mass loss variations
We present new numerical hydrodynamical modelling of the evolution of Asymptotic Giant Branch (AGB) mass loss fluctuations during the post-AGB/Planetary Nebula phase. These models show that after ionization, the observable effects of the mass loss fluctuations disappear in a few thousand years, consistent with the fact that only few PNe have been found to be surrounded by ‘rings’. We derive the...
متن کاملInsight into Agb and Post-agb Stellar Evolution with Fuse
FUSE spectroscopy has proved that extremely hot hydrogen-deficient post-AGB stars (PG1159 stars) display matter on their surface that usually remains hidden in the region between the Hand He-burning shells of the former AGB star. Hence, the spectral analysis of PG1159 stars allows to study directly the chemistry of this intershell region which is the outcome of complicated burning and mixing pr...
متن کاملStellar Evolution and Nucleosynthesis of Post-agb Stars
I discuss recent new models of post-Asymptotic Giant Branch stellar evolution. These models aim to clarify the evolutionary origin and status of a variety of hydrogen-deficient post-AGB stars such as central stars of planetary nebulae of Wolf-Rayet spectral type, PG1159 stars or Sakurai’s object. Starting with AGB models with overshoot such stars can evolve through one of four distinct channels...
متن کاملMass loss rates of a sample of irregular and semiregular M-type AGB-variables
We have determined mass loss rates and gas expansion velocities for a sample of 69 M-type irregular (IRV; 22 objects) and semiregular (SRV; 47 objects) AGB-variables using a radiative transfer code to model their circumstellar CO radio line emission. We believe that this sample is representative for the mass losing stars of this type. The (molecular hydrogen) mass loss rate distribution has a m...
متن کاملOn the Luminosity and Mass Loss of Galactic AGB Stars
As part of a reanalysis of Galactic Asymptotic Giant Branch stars (hereafter AGB stars) at infrared wavelengths, we discuss here two samples (the first of carbon-rich stars, the second of S stars) for which photometry in the nearand mid-IR and distance estimates are available. Whenever possible we searched also for mass-loss rates. The observed spectral energy distributions extended in all case...
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ژورنال
عنوان ژورنال: Symposium - International Astronomical Union
سال: 2000
ISSN: 0074-1809
DOI: 10.1017/s0074180900002424