SIMBAD references

2002A&A...384..452W - Astronomy and Astrophysics, volume 384, 452-459 (2002/3-3)

An improved mass-loss description for dust-driven superwinds and tip-AGB evolution models.


Abstract (from CDS):

We derive an improved description of dust-driven stellar mass-loss for the cool winds of carbon-rich tip-AGB stars. We use pulsating wind models in which the mass loss is driven by radiation pressure on dust grains, for C-rich chemistry. From a larger set of these models, selected for representative dynamical (pulsational velocity amplitude Δv, period P) and chemical (the εCO abundance ratio) input parameters, an improved approximative mass-loss formula has been derived which depends only on the stellar parameters (effective temperature Teff, luminosity L and mass M). Due to the detailed consideration of the chemistry and the physics of the dust nucleation and growth processes, there is a particularly strong dependence of the mass-loss rate {dot}(M) (in M/yr) on Teff: log{dot}(M)=8.86-1.95*logM/M-6.81*logT/K+2.47*logL/L. The dependence of the model mass-loss on the pulsational period has explicitly been accounted for in connection with the luminosity dependence, by applying an observed period-luminosity relation for C-rich Miras. We also apply the improved mass-loss description to our evolution models, and we revisit their tip-AGB mass-loss histories and the total masses lost, in comparison to our earlier work with a preliminary mass-loss description. While there is virtually no difference for the models in the lower mass range of consideration (Mi=1.0 to ≃1.3M), we now find more realistic, larger superwind mass-loss rates for larger stellar masses: i.e., {dot}(M) between ≃0.4 and 1.0x10–4M/yr for Mi between 1.85 and 2.65M, removing between 0.6 and 1.2M, respectively, during the final 30000yrs on the tip-AGB.

Abstract Copyright:

Journal keyword(s): stars: carbon - stars: circumstellar matter - stars: evolution - stars: interiors - stars: late-type - stars: mass loss

Simbad objects: 18

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