Stellar Structure and Mass Loss on the Upper AGB

Abstract

We examine the envelope properties of asymptotic giant branch (AGB) stars as they evolve on the upper AGB and during the early post-AGB phase. Due to the high mass loss rate, the envelope mass decreases by more than an order of magnitude. This makes the density profile below the photosphere much shallower, and the entropy profile much steeper. We discuss the possible role of these changes in the profiles in the onset of the high mass loss rate (superwind) and the large deviation from spherical mass loss at the termination of the AGB. We concentrate on the idea that the shallower density profile and steeper entropy profile allow the formation of cool magnetic spots, above which dust forms much more easily.

13 pages + 7 figures (postscript), accepted by MNRAS

Cited by in corpus (18)

• Energy and Angular Momentum Deposition During Common Envelope Evolution
• Solar-Like Cycle in Asymptotic Giant Branch Stars
• A New Look at the Evolution of Wolf-Rayet Central Stars of Planetary Nebulae
• Turbulent Dynamo in Asymptotic Giant Branch Stars
• Why a Single-Star Model Cannot Explain the Bipolar Nebula of Eta Carinae
• The Effects of Planets and Brown Dwarfs on Stellar Rotation and Mass-Loss
• Extrasolar Planets and the Rotation and Axisymmetrical mass loss of evolved stars
• Magnetic Flares on Asymptotic Giant Branch Stars
• Comparing Eta Carinae with the Red Rectangle
• Magnetic Activity in Stellar Merger Products
• Triggering Eruptive Mass Ejection in Luminous Blue Variables
• A Phenomenological Model for the Extended Zone Above AGB Stars
• A Superwind from Early Post-Red Giant Stars?
• Defining the Termination of the Asymptotic Giant Branch
• A hybrid steady-state magnetohydrodynamic dust-driven stellar wind model for AGB stars
• Photospheric Opacity and Over-Expanded Envelopes of Asymptotic Giant Branch Stars
• Planetary Nebulae in the Scheme of Binary Evolution
• Planets and Axisymmetric Mass Loss