J/MNRAS/404/1529 s-process in low-metallicity stars (Bisterzo+, 2010)
s-process in low-metallicity stars - I. Theoretical predictions.
Bisterzo S., Gallino R., Straniero O., Cristallo S., Kappeler F.
<Mon. Not. R. Astron. Soc., 404, 1529-1544 (2010)>
=2010MNRAS.404.1529B 2010MNRAS.404.1529B
ADC_Keywords: Atomic physics
Keywords: nuclear reactions, nucleosynthesis, abundances - stars: carbon -
stars: Population II
Abstract:
A large sample of carbon-enhanced metal-poor stars enriched in
s-process elements (CEMP-s) have been observed in the Galactic halo.
These stars of low mass (M∼0.9M☉) are located on the
main-sequence or the red-giant phase, and do not undergo third
dredge-up (TDU) episodes. The s-process enhancement is most plausibly
due to accretion in a binary system from a more massive companion when
on the asymptotic giant branch (AGB) phase (now a white dwarf). In
order to interpret the spectroscopic observations, updated AGB models
are needed to follow in detail the s-process nucleosynthesis. We
present nucleosynthesis calculations based on AGB stellar models
obtained with Frascati Raphson-Newton Evolutionary Code (FRANEC)
for low initial stellar masses and low metallicities. For a given
metallicity, a wide spread in the abundance of the s-process elements
is obtained by varying the amount of 13C and its profile in the
pocket, where the 13C(α, n)16O reaction is the major neutron
source, releasing neutrons in radiative conditions during the
interpulse phase. We also account for the second neutron source
22Ne(α,n)25Mg, partially activated during convective
thermal pulses.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 21 44 Theoretical predictions in percentage for
elements from Sr to Bi
tableb1.dat 101 77 Theoretical [El/Fe] predictions from He to Bi for
MAGBini=1.3M☉ (which undergoes 5 TPs
with TDU, n5) and [Fe/H] =-2.6 models, as the
13C-pocket changes (STx2 down to ST/150)
tableb2.dat 101 77 Theoretical [El/Fe] predictions from He to Bi for
MAGBini=1.4M☉ (which undergoes 10 TPs
with TDU, n10) and [Fe/H] =-2.6 models, as the
13C-pocket changes (STx2 down to ST/150)
tableb3.dat 101 77 Theoretical [El/Fe] predictions from He to Bi for
MAGBini=1.5M☉ (which undergoes 20 TPs
with TDU, n20) and [Fe/H] =-2.6 models, as the
13C-pocket changes (STx2 down to ST/150)
tableb4.dat 101 77 Theoretical [El/Fe] predictions from He to Bi for
MAGBini=2.0M☉ (which undergoes 26 TPs
with TDU, n26) and [Fe/H] =-2.6 models, as the
13C-pocket changes (STx2 down to ST/150)
tableb5.dat 101 77 Theoretical [El/Fe] predictions from He to Bi for
MAGBini=1.3 M☉ and two 13C-pockets
(ST and ST/12), as the metallicity changes
tableb6.dat 101 77 Theoretical [El/Fe] predictions from He to Bi for
MAGBini=1.5 M☉ and two 13C-pockets
(ST and ST/12), as the metallicity changes
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- El Element
4- 5 I2 --- Z Atomic number
7- 10 F4.1 % A(El) Percentage of element obtained by an average
of M=1.5 and 3.0M☉ models (Maver)
at [Fe/H]=-0.3 (1)
12- 15 F4.1 % U(El) Percentage element improved with cross section
measurements and solar abundances upgraded to
2009 at [Fe/H]=-0.3 (1)
17- 21 F5.2 --- [El/Eu] Normalization of the updated main-s
percentages to europium in logarithmic scale
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Note (1): Case ST (Stellar model in Table 2 of Arlandini et al.
(1999ApJ...525..886A 1999ApJ...525..886A)
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Byte-by-byte Description of file: tableb[1234].dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
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1- 2 A2 --- El Element
4- 5 I2 --- Z Atomic number
7- 11 F5.2 [-] ST*2 Theoretical [El/Fe] predictions for ST*2 (1)
13- 17 F5.2 [-] ST*1.3 Theoretical [El/Fe] predictions for ST*1.3 (1)
19- 23 F5.2 [-] ST Theoretical [El/Fe] predictions for ST (1)
25- 29 F5.2 [-] ST/1.5 Theoretical [El/Fe] predictions for ST/1.5 (1)
31- 35 F5.2 [-] ST/2 Theoretical [El/Fe] predictions for ST/2 (1)
37- 41 F5.2 [-] ST/3 Theoretical [El/Fe] predictions for ST/3 (1)
43- 47 F5.2 [-] ST/4.5 Theoretical [El/Fe] predictions for ST/4.5 (1)
49- 53 F5.2 [-] ST/6 Theoretical [El/Fe] predictions for ST/6 (1)
55- 59 F5.2 [-] ST/9 Theoretical [El/Fe] predictions for ST/9 (1)
61- 65 F5.2 [-] ST/12 Theoretical [El/Fe] predictions for ST/12 (1)
67- 71 F5.2 [-] ST/18 Theoretical [El/Fe] predictions for ST/18 (1)
73- 77 F5.2 [-] ST/24 Theoretical [El/Fe] predictions for ST/24 (1)
79- 83 F5.2 [-] ST/30 Theoretical [El/Fe] predictions for ST/30 (1)
85- 89 F5.2 [-] ST/45 Theoretical [El/Fe] predictions for ST/45 (1)
91- 95 F5.2 [-] ST/75 Theoretical [El/Fe] predictions for ST/75 (1)
97-101 F5.2 [-] ST/150 Theoretical [El/Fe] predictions for ST/150 (1)
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Note (1): 13C-pocket change: value 1.0 corresponds to the 13C-pocket value
in ST (stellar model of Table 2 of Arlandini et al. 1999ApJ...525..886A 1999ApJ...525..886A)
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Byte-by-byte Description of file: tableb5.dat tableb6.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- El Element name
4- 5 I2 --- Z Atomic number
7- 11 F5.2 [-] (-3.6) Prediction of [El/Fe] for ST, [Fe/H]=-3.6
13- 17 F5.2 [-] (-3.0) Prediction of [El/Fe] for ST, [Fe/H]=-3.0
19- 23 F5.2 [-] (-2.6) Prediction of [El/Fe] for ST, [Fe/H]=-2.6
25- 29 F5.2 [-] (-2.3) Prediction of [El/Fe] for ST, [Fe/H]=-2.3
31- 35 F5.2 [-] (-2.0) Prediction of [El/Fe] for ST, [Fe/H]=-2.0
37- 41 F5.2 [-] (-1.6) Prediction of [El/Fe] for ST, [Fe/H]=-1.6
43- 47 F5.2 [-] (-1.3) Prediction of [El/Fe] for ST, [Fe/H]=-1.3
49- 53 F5.2 [-] (-1.0) Prediction of [El/Fe] for ST, [Fe/H]=-1.0
55- 59 F5.2 [-] (-3.6)/12 Prediction of [El/Fe] for ST/12, [Fe/H]=-3.6
61- 65 F5.2 [-] (-3.0)/12 Prediction of [El/Fe] for ST/12, [Fe/H]=-3.0
67- 71 F5.2 [-] (-2.6)/12 Prediction of [El/Fe] for ST/12, [Fe/H]=-2.6
73- 77 F5.2 [-] (-2.3)/12 Prediction of [El/Fe] for ST/12, [Fe/H]=-2.3
79- 83 F5.2 [-] (-2.0)/12 Prediction of [El/Fe] for ST/12, [Fe/H]=-2.0
85- 89 F5.2 [-] (-1.6)/12 Prediction of [El/Fe] for ST/12, [Fe/H]=-1.6
91- 95 F5.2 [-] (-1.3)/12 Prediction of [El/Fe] for ST/12, [Fe/H]=-1.3
97-101 F5.2 [-] (-1.0)/12 Prediction of [El/Fe] for ST/12, [Fe/H]=-1.0
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 30-Nov-2010