J/A+A/466/641 Reaction rates of NeNa-MgAl chains in AGB stage (Izzard+, 2007)
Reaction rate uncertainties and the operation of the NeNa and MgAl chains during
HBB in intermediate-mass AGB stars.
Izzard R.G., Lugaro M., Karakas A.I., Iliadis C., van Raai M.
<Astron. Astrophys. 466, 641 (2007)>
=2007A&A...466..641I 2007A&A...466..641I
ADC_Keywords: Atomic physics ; Models, evolutionary
Keywords: nuclear Reactions, nucleosynthesis, abundances -
stars: AGB and post-AGB
Abstract:
We test the effect of proton-capture reaction rate uncertainties on
the abundances of the Ne, Na, Mg and Al isotopes processed by the NeNa
and MgAl chains during hot bottom burning (HBB) in asymptotic giant
branch (AGB) stars of intermediate mass between 4 and 6M☉
and metallicities between Z=0.0001 and 0.02. We provide uncertainty
ranges for the AGB stellar yields, for inclusion in galactic chemical
evolution models, and indicate which reaction rates are most important
and should be better determined.
Description:
We use a fast synthetic algorithm based on detailed AGB models. We run
a large number of stellar models, varying one reaction per time for a
very fine grid of values, as well as all reactions simultaneously.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table13.dat 97 576 Complete results for a relatively small subset of
synthetic models obtained by varying only the six most
uncertain reactions between their upper and lower limits
table13.tex 83 9450 LaTeX version of table13
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Byte-by-byte Description of file: table13.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- --- [M=]
3 I1 solMass Mass [4/6] Model initial mass (1)
5- 6 A2 --- --- [Z=]
7- 12 F6.4 --- Z Model initial Z abundance (1)
(0.0001, 0.004, 0.008, 0.02)
14- 15 A2 --- r1 [UL] 22Ne(p,γ)23Na reaction
upper (UL) or lower (LL) limit
17- 18 A2 --- r2 [UL] 23Na(p,γ)24Mg reaction
upper (UL) or lower (LL) limit
20- 21 A2 --- r3 [UL] 23Na(p,α)20Ne reaction
upper (UL) or lower (LL) limit
23- 24 A2 --- r4 [UL] 25Mg(p,γ)26Al->26^Mg reaction
upper (UL) or lower (LL) limit
26- 27 A2 --- r5 [UL] 26Mg(p,γ)27Al reaction
upper (UL) or lower (LL) limit
29- 30 A2 --- r6 [UL] 26Al(p,γ)27Si->27Al reaction
upper (UL) or lower (LL) limit
32- 37 F6.4 --- 20Ne 20Ne yield relative to control value (2)
39- 44 F6.4 --- 21Ne 21Ne yield relative to control value (2)
46- 51 F6.4 --- 22Ne 22Ne yield relative to control value (2)
53- 60 F8.4 --- 23Na 23Na yield relative to control value (2)
62- 68 F7.4 --- 24Mg 24Mg yield relative to control value (2)
70- 75 F6.4 --- 25Mg 25Mg yield relative to control value (2)
77- 82 F6.4 --- 26Mg 26Mg yield relative to control value (2)
84- 90 F7.5 --- 26Al 26Al yield relative to control value (2)
92- 97 F6.4 --- 27Al 27Al yield relative to control value (2)
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Note (1): Models considered have the parameters:
M=4 Z=0.0001;
M=5 Z=0.0001;
M=5 Z=0.004;
M=5 Z=0.008;
M=5 Z=0.02;
M=6 Z=0.0001;
M=6 Z=0.004;
M=6 Z=0.008;
M=6 Z=0.02
Note (2): Ratio of result yield to control value, where positive values
indicate extra production, negative values extra destruction,
and zero means no change.
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Acknowledgements:
M. Lugaro, lugaro(at)phys.uu.nl
(End) Patricia Vannier [CDS] 15-Feb-2007