100-yr mass-loss modulations on the asymptotic giant branch

Mass loss on the Asymptotic Giant Branch

Mass loss on the Asymptotic Giant Branch provides the origin of planetary nebulae. This paper reviews several relevant aspects of AGB evolution: pulsation properties, mass loss formalisms and time variable mass loss, evidence for asymmetries on the AGB, binarity, ISM interaction, and mass loss at low metallicity. There is growing evidence that mass loss on the AGB is already asymmetric, but wit...

Mass loss of stars on the asymptotic giant branch

As lowand intermediate-mass stars reach the asymptotic giant branch (AGB), they have developed into intriguing and complex objects that are major players in the cosmic gas/dust cycle. At this stage, their appearance and evolution are strongly affected by a range of dynamical processes. Large-scale convective flows bring newlyformed chemical elements to the stellar surface and, together with pul...

Crystallinity versus mass-loss rate in Asymptotic Giant Branch stars

Infrared Space Observatory (ISO) observations have shown that O-rich Asymptotic Giant Branch (AGB) stars exhibit crystalline silicate features in their spectra only if their mass-loss rate is higher than a certain threshold value. Usually, this is interpreted as evidence that crystalline silicates are not present in the dust shells of low mass-loss rate objects. In this study, radiative transfe...

The Asymptotic Giant Branch

Mass loss and yield uncertainty in low-mass asymptotic giant branch stars

We investigate the uncertainty in surface abundances and yields of asymptotic giant branch (AGB) stars. We apply three different mass-loss laws to a 1.5-M star of metallicity Z = 0.008 at the beginning of the thermally pulsing-asymptotic giant branch (TP-AGB) phase. Efficient third dredge-up is found even at very low envelope mass, contrary to previous simulations with other evolution codes. We...