Related papers: Dynamos and Chemical Mixing in Evolved Stars
It is well appreciated that the description of overadiabatic convection affects the structure of the envelopes of luminous asymptotic giant branch (AGB) stars in the phase of ``hot bottom burning '' (HBB). We stress that this important…
Encoded in the time- and wavelength dependent properties of pulsating AGB stars are the underlying fundamental parameters of mass, composition and evolutionary state. However, the standard technique of placing stars on a HR diagram, even…
Stars with masses between roughly 1 and 8~$M_\odot$ end their lives on the asymptotic giant branch (AGB), when intense mass loss takes place. The outflows are generally accepted to be driven by radiation pressure acting on dust grains that…
The determinations of element abundances in red-giant stars and in particular in AGB stars are reviewed and the resulting abundances are compared with those obtained for planetary nebulae in the Galaxy and in nearby galaxies. The problems,…
The purpose of this paper is to improve the modeling of the mixing of chemical elements that occurs in stellar radiation zones. In addition to the classical rotational mixing considered in our previous paper, which results of the combined…
Context: Intermediate-mass asymptotic giant branch (AGB) stars influence Galactic lithium evolution by ejecting surface material (including Li) via stellar winds. Internal gravity waves (IGW), excited by convective motions, drive turbulent…
Two types of models for the formation of semi-periodic concentric multiple shells (M-shells) around asymptotic giant branch (AGB) stars and in planetary nebulae are compared against observations. Models that attribute the M-shells to…
We present a scenario to explain the lithium-rich phase which occurs on the red giant branch at the so-called bump in the luminosity function. The high transport coefficients required to enhance the surface lithium abundance are obtained in…
An analysis of high-resolution near-infrared spectra of a sample of 45 asymptotic giant branch (AGB) stars towards the Galactic bulge is presented. The sample consists of two subsamples, a larger one in the inner and intermediate bulge, and…
The commonly accepted mechanism governing the formation of the nascent wind in oxygen-rich AGB stars combines an initial boost above the photosphere, given by shock waves resulting from stellar pulsations and convective cell granulation,…
We discuss and illustrate contributions that optical interferometry has made on our current understanding of cool evolved stars. We include red giant branch (RGB) stars, asymptotic giant branch (AGB) stars, and red supergiants (RSGs).…
Context: Observations of asymptotic giant branch (AGB) stars with increasing spatial resolution reveal new layers of complexity of atmospheric processes on a variety of scales. Aim: To analyze the physical mechanisms that cause asymmetries…
Context: Stars evolving through the asymptotic giant branch (AGB) phase provide significant feedback to their host system, in form of both gas enriched in nuclear-burning products and dust formed in their winds, which they eject into the…
Low and intermediate mass stars with super solar metallicities comprise a known portion of the universe. Yet yields for asymptotic giant branch (AGB) stars with metallicities greater than $Z=0.04$ do not exist in the literature. This…
We explore the role that red giants might play in the central regions of Active Galactic Nuclei. Due to their large radii and the low binding energy of the stellar envelope, giants are vulnerable to envelope stripping from collisions with…
The slow, dense winds observed in evolved asymptotic giant branch (AGB) stars are usually attributed to a combination of dust formation in the dynamical inner atmosphere and momentum transfer from stellar photons interacting with the newly…
The origin of chemically peculiar stars and non-zero eccentricity in evolved close binaries have been long-standing problems in binary stellar evolution. Answers to these questions may trace back to an intense mass transfer during AGB…
Circumbinary discs are commonly observed around post-asymptotic giant branch (AGB) systems and are known to play an important role in their evolution. Several studies have pointed out that a circumbinary disc interacts through resonances…
Post-RGB and post-AGB binaries consist of a primary star that has recently evolved off either the RGB or AGB after losing most of its envelope, and a main-sequence companion. They are distinguished by luminosities below and above the RGB…
Binary stars can interact via mass transfer when one member (the primary) ascends onto a giant branch. The amount of gas ejected by the binary and the amount of gas accreted by the secondary over the lifetime of the primary influence the…