
Mass loss and yield uncertainty in low‐mass asymptotic giant branch stars
Author(s) -
Stancliffe Richard J.,
Jeffery C. Simon
Publication year - 2007
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2006.11363.x
Subject(s) - asymptotic giant branch , physics , planetary nebula , metallicity , astrophysics , stars , red giant branch , envelope (radar) , giant star , yield (engineering) , astronomy , telecommunications , radar , computer science , thermodynamics
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 find that the yield of carbon is uncertain by about 15 per cent and for most other light elements the yield is uncertain at the level of 20–80 per cent. For iron group elements, the uncertainty varies from around 30 per cent for the more‐abundant species to over a factor of 2 for the less‐abundant radioactive species, like 60 Fe. The post‐AGB surface abundances for this mass and metallicity are much more uncertain due to the dilution of dredged‐up material in differing envelope masses in the later stages of the models. Our results are compared to known planetary nebula and post‐AGB abundances. We find that the models are mostly consistent with observations but we are unable to reproduce observations of some of the isotopes.