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J/ApJ/797/44    Evolution and nucleosynthesis of AGB stars     (Fishlock+, 2014)

Evolution and nucleosynthesis of asymptotic giant branch stellar models of low metallicity. Fishlock C.K., Karakas A.I., Lugaro M., Yong D. <Astrophys. J., 797, 44 (2014)> =2014ApJ...797...44F (SIMBAD/NED BibCode)
ADC_Keywords: Stars, giant ; Stars, masses ; Effective temperatures ; Abundances ; Models, evolutionary Keywords: nuclear reactions, nucleosynthesis, abundances - stars: abundances - stars: AGB and post-AGB Abstract: We present stellar evolutionary tracks and nucleosynthetic predictions for a grid of stellar models of low- and intermediate-mass asymptotic giant branch (AGB) stars at Z=0.001 ([Fe/H]=-1.2). The models cover an initial mass range from 1 M to 7 M. Final surface abundances and stellar yields are calculated for all elements from hydrogen to bismuth as well as isotopes up to the iron group. We present the first study of neutron-capture nucleosynthesis in intermediate-mass AGB models, including a super-AGB model, of [Fe/H]=-1.2. We examine in detail a low-mass AGB model of 2 M where the 13C(α,n)16O reaction is the main source of neutrons. We also examine an intermediate-mass AGB model of 5 M where intershell temperatures are high enough to activate the 22Ne neutron source, which produces high neutron densities up to ∼1014 n/cm3. Hot bottom burning is activated in models with M≥3 M. With the 3 M model, we investigate the effect of varying the extent in mass of the region where protons are mixed from the envelope into the intershell at the deepest extent of each third dredge-up. We compare the results of the low-mass models to three post-AGB stars with a metallicity of [Fe/H]~-1.2. The composition is a good match to the predicted neutron-capture abundances except for Pb and we confirm that the observed Pb abundances are lower than what is calculated by AGB models. Description: We calculate AGB stellar models for a range of initial masses from 1 M to 7 M with a metallicity of Z=0.001 ([Fe/H]=-1.2) and a helium abundance of Y=0.25. For the purposes of this study, we define the low-mass models to be those with an initial mass up to and including 3 M, and the intermediate-mass models, 3.25 M and above. Each stellar model is evolved from the zero-age main sequence to near the end of the AGB phase when the majority of the convective envelope is lost by stellar winds. A two-step procedure is performed to calculate the structure and detailed nucleosynthesis for each stellar model. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 174 772 Model structural properties for each thermal pulse table8.dat 104 1840 The isotopic yields table9.dat 104 1328 The elemental yields table10.dat 199 114 The final surface abundances for each isotope table11.dat 62 1344 The final surface abundance of each element
See also: J/ApJ/696/797 : Evolution and yields of low-mass AGB stars (Cristallo+, 2009) J/MNRAS/403/1413 : Updated stellar yields from AGB models (Karakas, 2010) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 4 F4.2 Msun Mass [1.0/7.0] Initial model mass (G1) 6- 8 I3 --- Pulse [1/135] Pulse number 10- 19 E10.4 Msun Mcore Core mass 21- 30 E10.4 Msun Mcsh Maximum mass of intershell convection zone 32- 41 E10.4 yr tcsh Duration of intershell convection 43- 52 E10.4 Msun MDred Mass dredged into envelope 54- 63 E10.4 --- lamb Third dredge-up efficiency 65- 74 E10.4 K THesh Maximum He-shell temperature 76- 85 E10.4 K Tbce Maximum temperature at base of convective envelope (2) 87- 96 E10.4 K THsh Maximum H-shell temperature (2) 98-107 E10.4 yr tip Interpulse period 109-118 E10.4 Msun Mtot Total mass 120-129 E10.4 Lsun Lmax Maximum radiated luminosity (2) 131-140 E10.4 Lsun LHemax Maximum He-luminosity during a thermal pulse 142-151 E10.4 Rsun Rmax Maximum radius (2) 153-163 E11.4 mag mBol Bolometric magnitude 165-174 E10.4 K Teff Effective temperature at maximum radius
Note (2): During previous interpulse period.
Byte-by-byte Description of file: table8.dat table9.dat
Bytes Format Units Label Explanations
1- 4 F4.2 Msun Mass [1.0/7.0] Initial model mass (G1) 6- 7 A2 --- El ? Element identifier 9- 10 I2 --- Z [0/84]? Atomic number 12- 15 A4 --- Species ? Species identifier 17- 18 I2 --- A [1/70]? Atomic mass number 20- 33 E14.7 Msun M Net stellar yield (2) 35- 47 E13.7 Msun Mlost Amount lost from stellar wind 49- 61 E13.7 Msun M0 Total mass expelled (3) 63- 75 E13.7 --- <X> Average mass fraction in the wind 77- 89 E13.7 --- X0 Initial mass fraction 91-104 E14.7 [-] f Production factor (4)
Note (2): As defined in Equation 4. Note (3): During the stellar lifetime multiplied by the initial mass fraction. Note (4): Defined as log10[<X>/X0].
Byte-by-byte Description of file: table10.dat
Bytes Format Units Label Explanations
1- 4 A4 --- Species Species identifier 6- 7 I2 --- A [1/70] Atomic mass number 9- 19 E11.5 --- Abd-1 Surface abundance in 1 solar mass model (1) 21- 31 E11.5 --- Abd-1.25 Surface abundance in 1.25 solar mass model (1) 33- 43 E11.5 --- Abd-1.5 Surface abundance in 1.5 solar mass model (1) 45- 55 E11.5 --- Abd-2 Surface abundance in 2 solar mass model (1) 57- 67 E11.5 --- Abd-2.25 Surface abundance in 2.25 solar mass model (1) 69- 79 E11.5 --- Abd-2.5 Surface abundance in 2.5 solar mass model (1) 81- 91 E11.5 --- Abd-2.75 Surface abundance in 2.75 solar mass model (1) 93-103 E11.5 --- Abd-3 Surface abundance in 3 solar mass model (1) 105-115 E11.5 --- Abd-3.25 Surface abundance in 3.25 solar mass model (1) 117-127 E11.5 --- Abd-3.5 Surface abundance in 3.5 solar mass model (1) 129-139 E11.5 --- Abd-4 Surface abundance in 4 solar mass model (1) 141-151 E11.5 --- Abd-4.5 Surface abundance in 4.5 solar mass model (1) 153-163 E11.5 --- Abd-5 Surface abundance in 5 solar mass model (1) 165-175 E11.5 --- Abd-5.5 Surface abundance in 5.5 solar mass model (1) 177-187 E11.5 --- Abd-6 Surface abundance in 6 solar mass model (1) 189-199 E11.5 --- Abd-7 Surface abundance in 7 solar mass model (1)
Note (1): In Y where Y=X/A and X is the mass fraction and A is the atomic mass.
Byte-by-byte Description of file: table11.dat
Bytes Format Units Label Explanations
1- 4 F4.2 Msun Mass [1.0/7.0] Initial model mass (G1) 6- 7 A2 --- El Element identifier 9- 10 I2 --- Z [1/84] Atomic number 12- 20 F9.6 [-] loge Log abundance (2) 22- 30 F9.6 [-] [X/H] Log abundance relative to hydrogen (3) 32- 40 F9.6 [-] [X/Fe] Log abundance relative to iron (3) 42- 50 F9.6 [-] [X/O] Log abundance relative to oxygen (3) 52- 62 E11.5 --- X Mass fraction
Note (2): Where loge=log10(NA/NH)+12 and NA and NH are abundances of element A and H. Note (3): Where [X/Y]=log10(NX/NY)-log10(NX/NY)solar and NX/NY are the abundances of elements X and Y.
Global notes: Note (G1): All models have Z=0.001.
History: From electronic version of the journal
(End) Prepared by [AAS], Tiphaine Pouvreau [CDS] 16-Aug-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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