Related papers: Observed relationship between CO2-1 and dust emiss…
We present optical high-resolution spectra of a sample of sixteen post-AGB stars and IRC +10216. Of the post-AGB stars, ten show C2 Phillips and Swan and CN Red System absorption, one CH+ emission, one CH+ absorption, and four without any…
Surface densities of gas, dust and stars provide a window into the physics of star-formation that, until the advent of high-resolution far-infrared/sub-millimeter observations, has been historically difficult to assess amongst dusty…
There is a group of binary post-AGB stars that show a conspicuous NIR excess, usually assumed to arise from hot dust in very compact possibly rotating disks. These stars are surrounded by significantly fainter nebulae than the "standard",…
A study is made of a sample of 58 dust-enshrouded Asymptotic Giant Branch (AGB) stars (including 2 possible post AGB stars), of which 27 are carbon-rich and 31 are oxygen-rich. These objects were originally identified by Jura & Kleinmann as…
Luminous infrared galaxies ($L_{\rm{IR}}>10^{11} L_{\odot}$) are often associated with interacting galactic systems and are thought to be powered by merger--induced starbursts and/or dust--enshrouded AGN. In such systems, the evolution of…
We present IRAM-30m Telescope $^{12}$CO and $^{13}$CO observations of a sample of 55 luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) in the local universe. This sample is a subset of the Great Observatory All-Sky LIRG Survey…
Detailed atmospheric abundances have been calculated for a sample of A-G supergiant stars with IR fluxes and/or high galactic latitudes. HD 172481 and HD 158616 show clear indications of being post-AGB stars that have experienced third…
We used models of thermally-pulsing asymptotic giant branch (AGB) stars, that also describe the dust-formation process in the wind, to interpret the combination of near- and mid-infrared photometric data of the dwarf galaxy IC 1613. This is…
The observational data guiding the theoretical chemical evolutionary models of AGB stars come mainly from the analysis of intrinsic and extrinsic s-process enriched objects. The first are the stars of the M-MS-S-SC-C star sequence which is…
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…
Asymptotic giant branch (AGB) stars are significant contributors to the chemical enrichment of the interstellar medium (ISM) of galaxies. It is therefore essential to constrain the AGB contribution to the dust budget in galaxies. Recent…
Modern population synthesis models estimate that 50% of the restframe K-band light is produced by TP-AGB stars during the first Gyr of a stellar population, with a substantial fraction continuing to be produced by the TP-AGB over a Hubble…
We aim to (1) set up simple and general analytical expressions to estimate mass-loss rates of evolved stars, and (2) from those calculate estimates for the mass-loss rates of asymptotic giant branch (AGB), red supergiant (RSG), and yellow…
The observations and comprehensive study of intermediate initial mass stars at the late stages of evolution, and after the asymptotic giant branch (AGB) in particular, are of crucial importance to identify the common properties for the…
We have performed new medium resolution spectroscopy, optical and near infrared photometry to monitor the variability of the AGB carbon star V 381 Lac. Our observations revealed rapid and deep changes in the spectrum and extreme variability…
During their thermally pulsing phase, Asymptotic Giant Branch (AGB) stars eject material that forms extended dusty envelopes. Visible polarimetric imaging found clumpy dust clouds within two stellar radii of several oxygen-rich stars.…
Non-variable OH/IR stars are thought to have just left the asymptotic giant branch (AGB) phase. In this conventional picture, they must still show strong circumstellar extinction caused by the dust ejected during the AGB phase, and the…
This paper describes observations of a new phenomenon in evolved mass-losing AGB stars: the presence of two winds with different expansion velocities. CO(2-1) and CO(3-2) line emission was observed for 45 AGB stars at high velocity…
We have performed mm-wave observations with the IRAM 30m telescope of the 12CO J=2-1 and J=1-0, 13CO J=2-1 and J=1-0, and SiO J=5-4 transitions in the symbiotic stars R Aqr, CH Cyg, and HM Sge. The data were analyzed by means of a simple…
During their late pulsating phase, AGB stars expel most of their mass in the form of massive dusty envelopes, an event that largely controls the composition of interstellar matter. The envelopes, however, are distant and opaque to visible…