相关论文: Evolution from AGB to planetary nebula in the MSX …
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…
Recent improvements in globular cluster colour-magnitude diagrams, coupled with an increase in large-sample spectroscopic abundance studies of cluster giants, finally allow some attempts at a statistically meaningful comparison of the…
The present article is written in the wake of a recently published study of the relation between the light curves of Long Period Variables and their evolution along the Asymptotic Giant Branch (AGB). It introduces a pair of new parameters…
Mass-loss from evolved stars chemically enriches the ISM. Stellar winds from massive stars and their explosions as SNs shape the ISM and trigger star formation. Studying evolved stars is fundamental for understanding galaxy formation and…
Dynamical stellar-evolution modeling through the AGB phase reveals that radial pulsations with very fast-growing amplitudes develop if the luminosity to mass ratio of stars with tenuous envelopes exceeds a critical limit. An instability…
We study the chemical abundances of a wide sample of 142 Galactic planetary nebulae (PNe) with good quality observations, for which the abundances have been derived more or less homogeneously, thus allowing a reasonable comparison with…
We present Spitzer/IRS observations of a small sample of heavily obscured IRAS sources displaying both the infrared and OH maser emission characteristic of OH/IR stars on the asymptotic giant branch (AGB), but also radio continuum emission…
Using a radiation-hydrodynamics code I follow the formation of planetary nebulae around stars of different mass. Because a more massive central star evolves much faster than a lower mass one, it is to be expected that this will affect the…
Despite numerous efforts, the transition from Asymptotic Giant Branch (AGB) stars to Planetary Nebulae (PN) is a poorly understood phase of stellar evolution. We have therefore carried out interferometric (VLA) radio observations of a…
Post-asymptotic giant branch (post-AGB) binaries are surrounded by massive disks of gas and dust that are similar to protoplanetary disks around young stars. We assembled a catalog of all known Galactic post-AGB binaries with disks. We…
Using 766 compact objects from a survey of the galactic Plane in the 1612-MHz OH line, new light is cast on the infrared properties of evolved stars on the TP-AGB and beyond. The usual mid-infrared selection criteria, based on IRAS colours,…
We present new spectro-photometric NIR observations of 16 post-starburst galaxies especially designed to test for the presence of strong carbon features of thermally pulsing AGB (TP-AGB) stars, as predicted by recent models of stellar…
We present nucleosynthesis predictions (HeCNOCl) from asymptotic giant branch (AGB) models, with diffusive overshooting from all the convective borders, in the metallicity range Z/4 < Z < 2Zsun. They are compared to recent precise nebular…
The spectro-photometric properties of galaxies in galaxy formation models are obtained by combining the predicted history of star formation and mass accretion with the physics of stellar evolution through stellar population models. In the…
The results from a Hubble Space Telescope (HST) snapshot survey of post-AGB objects are shown. The aim of the survey is to complement existing HST images of PPN and to connect various types of nebulosities with physical and chemical…
We find that AGB stars separate in the 25-12 vs. 12-K color-color diagram according to their chemistry (O, S vs. C) and variability type (Miras vs. SRb/Lb). While discrimination according to the chemical composition is not surprising, the…
Blue horizontal branch and UV bright stars in several globular clusters are analysed spectroscopically and the results are compared with predictions of stellar evolutionary theory. We find that the distribution of temperatures and surface…
The mass loss properties of carbon AGB stars are not very well constrained at present. A variety of empirical or theoretical formulae with different parameterisations are available in the literature and the agreement between them is…
Late asymptotic giant branch (AGB) and early post-AGB stars which are progenitors of planetary nebulae lose mass at extremely high rate, in what is termed a superwind. We show that the existence of this superwind during the post-AGB phase…
The asymptotic giant branch (AGB) phase of stellar evolution is common to most stars of low and intermediate mass. Most of the carbon and nitrogen in the Universe is produced by AGB stars. The final fate of the AGB envelopes are represented…