Circumstellar Envelopes as AGB Mass-Loss Signatures

Villaver, E.; García-Segura, G.; Manchado, A.
Bibliographical reference

Why Galaxies Care About AGB Stars: Their Importance as Actors and Probes. ASP Conference Series, Vol. 378, proceedings of the conference held 7-11 August 2006 at University Campus, Vienna, Austria. Edited by F. Kerschbaum, C. Charbonnel, and R. F. Wing. San Francisco: Astronomical Society of the Pacific, 2007., p.345

Advertised on:
11
2007
Number of authors
3
IAC number of authors
1
Citations
1
Refereed citations
1
Description
Low- and intermediate-mass stars (1--8 M&sun;) lose up to 80 % of their initial mass during the Asymptotic Giant Branch (AGB) phase. Heavy mass loss is the signature of the late AGB phase: at uncertain rates of 10-6 to 10-3 M&sun; yr-1, on timescales of ˜ 10^5--10^6 yr, it removes up to 7 M&sun; of stellar material. We have investigated the dynamical interaction of these winds with their interstellar medium (ISM) by using a numerical code and the wind history predicted by stellar evolution. Our aim is to allow a comparison between the AGB mass-loss rate predictions and observations of planetary nebula and AGB shells. According to our simulations, large regions (up to 2.5 pc) of neutral gas surrounding the molecular envelopes of AGB stars are expected. These large regions of gas are formed from the mass loss experienced by the star during AGB evolution and are strongly linked to the assumed timescales of heavy mass-loss rates.