J/A+A/454/917 Abundances of 26 barium stars. II. (Allen+, 2006)
Analysis of 26 barium stars.
II. Contributions of s-, r-, and p-processes in the production of heavy elements
Allen D.M., Barbuy B.
<Astron. Astrophys. 464, 917 (2006)>
=2006A&A...454..917A 2006A&A...454..917A
ADC_Keywords: Stars, barium ; Stars, atmospheres ; Atomic physics
Keywords: nuclear reactions, nucleosynthesis, abundances - stars: abundances
Abstract:
The aim of this work is to quantify the contributions of the s-, r-,
and p-processes for the total abundance of heavy elements from
abundances derived for a sample of 26 barium stars. The abundances of
the sample stars were compared to those of normal stars, thus
identifying the fraction relative to the main component of the
s-process s.
The fittings of the sigmaN curves (neutron-capture cross-section times
abundance, plotted against atomic mass number) for the sample stars
suggest that the material from the companion asymptotic giant branch
star had approximately the solar isotopic composition as concerns
fractions of abundances relative to the s-process main component.
Description:
Table 2 contains abundances obtained from least-square fittings for
normal stars with metallicities corresponding to our sample of barium
stars. first line of the set corresponds to the logarithm of the total
abundance (log(eps(X))) determined directly from the least square
fittings. The second line corresponds to the abundance fraction
(epsilons(X)) relative to the s-process main component, and the
third and forth lines correspond to the abundance fractions relative
to the r- and p-processes (epsilonr(X) epsilonp(X)), respectively.
The last line corresponds to the sum of abundances from other
processes except the s-process main component.
Table 6 contains the results of the abundance distribution for the s-,
r-, and p-processes for the sample of barium stars and abundance
fractions of the s-process main component for normal stars. sigmaN and
sigmaN(Si): cross-section times abundance fraction corresponding to
the s-process main component taking the overabundance of barium stars
into account on the usual scale and Si scale, respectively;
sigmaN(gs): cross-section times abundance fraction corresponding to
the s-process main component without the overabundance of barium
stars, i.e., by using the solar distribution on the total abundance.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 37 26 Star positions (from Simbad)
table2.dat 185 130 Abundance distribution for s-, r-, and
p-processes in normal stars
table6.dat 172 1617 Isotopic distribution for heavy elements in
barium stars
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See also:
J/A+A/454/895 : Abundances of 26 barium stars. I. (Allen+, 2006)
II/192 : UBV Photometry of Barium Stars (Watanabe+ 1993)
V/81 : Taxonomy of Barium Stars (Lu 1991)
J/A+A/319/881 : Ba II strength of barium stars (Gomez+ 1997)
J/A+A/321/L9 : Barium stars in the HR diagram (Bergeat+ 1997)
J/A+A/372/245 : Infrared properties of barium stars (Chen+, 2001)
J/AZh/79/909 : Chemical abundances in barium stars (Boyarchuk+, 2002)
J/A+A/397/257 : Chemical compositions of four barium stars (Liang+, 2003)
J/AZh/80/704 : Studies of classical barium stars (Antipova+, 2003)
J/AZh/81/658 : Equivalent widths of 9 barium stars (Antipova+, 2004)
Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name HD, HR, or BD designation
18- 19 I2 h RAh Right ascension (J2000)
21- 22 I2 min RAm Right ascension (J2000)
24- 27 F4.1 s RAs Right ascension (J2000)
29 A1 --- DE- Declination sign (J2000)
30- 31 I2 deg DEd Declination (J2000)
33- 34 I2 arcmin DEm Declination (J2000)
36- 37 I2 arcsec DEs Declination (J2000)
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name HD, HR, or BD designation
12- 16 F5.2 [Sun] [Fe/H] Metallicity
18- 23 A6 --- Param Kind of abundance (logarithm of the total
value or fraction for the process) (1)
24- 29 F6.2 --- abSr Abundances for Sr
31- 35 F5.2 --- e_abSr Uncertainties on abundances for Sr
37- 42 F6.2 --- abY Abundances for Y
44- 48 F5.2 --- e_abY Uncertainties on abundances for Y
50- 55 F6.2 --- abZr Abundances for Zr
57- 61 F5.2 --- e_abZr Uncertainties on abundances for Zr
63- 67 F5.2 --- abMo Abundances for Mo
69- 73 F5.2 --- e_abMo Uncertainties on abundances for Mo
75- 79 F5.2 --- abBa Abundances for Ba
81- 85 F5.2 --- e_abBa Uncertainties on abundances for Ba
87- 91 F5.2 --- abLa Abundances for La
93- 96 F4.2 --- e_abLa Uncertainties on abundances for La
98-102 F5.2 --- abCe Abundances for Ce
104-107 F4.2 --- e_abCe Uncertainties on abundances for Ce
109-113 F5.2 --- abPr Abundances for Pr
115-118 F4.2 --- e_abPr Uncertainties on abundances for Pr
120-124 F5.2 --- abNd Abundances for Nd
126-129 F4.2 --- e_abNd Uncertainties on abundances for Nd
131-135 F5.2 --- abSm Abundances for Sm
137-140 F4.2 --- e_abSm Uncertainties on abundances for Sm
142-146 F5.2 --- abEu Abundances for Eu
148-151 F4.2 --- e_abEu Uncertainties on abundances for Eu
153-157 F5.3 --- abGd Abundances for Gd
159-163 F5.3 --- e_abGd Uncertainties on abundances for Gd
165-168 F4.2 --- abDy Abundances for Dy
170-173 F4.2 --- e_abDy Uncertainties on abundances for Dy
175-179 F5.2 --- abPb Abundances for Pb
181-185 F5.2 --- e_abPb Uncertainties on abundances for Pb
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Note (1): Kind of abundances as follows:
logEps = logarithm of the total abundance determined directly from
the least square fittings
Eps_s = abundance fraction relative to the s-process main component
Eps_r = abundance fraction relative to the r-process
Eps_p = abundance fraction relative to the p-process
Eps_o = sum of abundances from other processes except the
s-process main component
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name HD, HR, or BD designation
12- 14 I3 --- A Atomic mass
16- 17 A2 --- Element Element code
19- 27 F9.3 --- Epss ? Fractions of total abundance relative to
the main component of the s-process (1)
29- 36 F8.3 --- e_Epss ? Uncertainty for the fractions of total
abundance relative to the main component
of the s-process
38- 41 F4.1 --- Epssw ? Fractions of total abundance relative to
the weak component of the s-process (1)
43- 46 F4.1 --- e_Epssw ? Uncertainty on the fractions of total
abundance relative to the weak component
of the s-process
47- 51 F5.2 --- Epsst ? Fractions of total abundance relative to
the strong component of the s-process (1)
53- 57 F5.2 --- e_Epsst ? Uncertainty on the fractions of total
abundance relative to the strong
component of the s-process
61- 65 F5.2 --- Epsr ? Fractions of total abundance relative to
the r-process (1)
70- 74 F5.2 --- e_Epsr ? Uncertainty on the fractions of total
abundance relative to the r-process
78- 84 F7.4 --- Epsp ? Fractions of total abundance relative to
the p-process (1)
87- 92 F6.4 --- e_Epsp ? Uncertainty on the fractions of total
abundance relative to the p-process
96-100 I5 --- SigmaN ? SigmaN on the usual scale
104-108 I5 --- e_SigmaN ? Uncertainty on sigmaN on the usual scale
111-118 F8.4 --- Epssn ? Fractions of total abundance relative to
the main component of the s-process for
normal stars (1)
121-128 F8.4 --- e_Epssn ? Uncertainty on the s-fraction for normal
stars
130-139 F10.4 --- diff ? Difference between the s-fractions for
barium and normal stars
142-150 E9.3 --- sigmaN(Si) ? sigmaN on the Si scale
153-161 E9.3 --- e_sigmaN(Si) ? Uncertainty on sigmaN on the Si scale
164-172 E9.3 --- sigmaN(gs) ? sigmaN with the solar distribution
for the total abundance
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Note (1): These abundances are not given in logarithmic form.
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Acknowledgements:
Dinah Moreira Allen, dinah(at)astro.iag.usp.br
(End) Patricia Vannier [CDS] 18-May-2006