J/MNRAS/412/843 SAGA extremely metal-poor stars (Suda+, 2011)
The stellar abundances for galactic archaeology (SAGA) data base.
II. Implications for mixing and nucleosynthesis in extremely metal-poor stars
and chemical enrichment of the galaxy.
Suda T., Yamada S., Katsuta Y., Komiya Y., Ishizuka C., Aoki W.,
Fujimoto M.Y.
<Mon. Not. R. Astron. Soc., 412, 843-874 (2011)>
=2011MNRAS.412..843S 2011MNRAS.412..843S
ADC_Keywords: Stars, population II ; Stars, metal-deficient ; Abundances
Keywords: stars: abundances - stars: AGB and post-AGB - binaries: general -
stars: carbon - stars: evolution - ISM: evolution
Abstract:
We discuss the characteristics of known extremely metal-poor (EMP)
stars in the Galaxy using the Stellar Abundances for Galactic
Archaeology (SAGA) data base. We find the transition of the initial
mass function to be at [Fe/H]~-2 from the viewpoint of the
distribution of carbon abundance and the frequency of carbon-enhanced
stars. Analyses of carbon-enhanced stars in our sample suggest that
nucleosynthesis in asymptotic giant branch (AGB) stars can contribute
to carbon enrichment in a different way depending on whether the
metallicity is above or below [Fe/H]~-2.5, which is consistent
with the current models of stellar evolution at low metallicity.
Description:
We extend the data set compiled in the SAGA data base by covering
papers published by the end of 2009, as compared with 2007 December in
Paper I (Suda et al., 2008PASJ...60.1159S 2008PASJ...60.1159S). The data compilation
reaches back to 1994, depending on the availability of data tables in
electronic format that is considered technically important for our
compilation process.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 88 61 Classification of CEMP (Carbon-Enhanced Metal-Poor)
stars in the SAGA database (Stellar Abundances for
Galactic Archaeology), based on Table 1
tablea2.dat 89 65 Classification of C-rich groups in the SAGA
database, based on Table 1
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See also:
J/A+A/403/1105 : Extremely metal-poor giants equivalent widths (Francois+ 2003)
J/AJ/128/2402 : Extremely metal-poor star candidates abundances (Lai+, 2004)
J/AJ/132/137 : Abundances of extremely metal-poor carbon stars (Cohen+, 2006)
J/A+A/490/769 : Yields from extremely metal-poor stars (Campbell+, 2008)
J/A+A/501/519 : Extremely metal-poor turnoff stars abund. (Bonifacio+, 2009)
Byte-by-byte Description of file: tablea[12].dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Type Type of CEMP or C-rich (1)
14- 26 A13 ---- Name Object name
28- 31 I4 K Teff Effective temperature
33- 36 F4.2 [cm/s2] logg Surface gravity
38- 42 F5.2 [Sun] [Fe/H] Metallicity
44- 47 F4.2 [Sun] [C/Fe] Carbon abundance
49 A1 --- l_[N/Fe] Limit flag on [N/Fe]
50- 54 F5.2 [Sun] [N/Fe] ?=- Nitrogen abundance
56 A1 --- l_[O/Fe] Limit flag on [O/Fe]
57- 60 F4.2 [Sun] [O/Fe] ?=- Oxygen abundance
62 A1 --- l_[Ba/Fe] Limit flag on [Ba/Fe]
63- 67 F5.2 [Sun] [Ba/Fe] ?=- Barium abundance
69 A1 --- l_[Eu/Fe] Limit flag on [Eu/Fe]
70- 74 F5.2 [Sun] [Eu/Fe] ?=- Europium abundance
76 A1 --- s/r [sr] Dominant source for neutron-capture
elements, slow- or rapid-process (2)
78- 80 A3 --- Bin [yes ] Binarity
82- 89 F8.3 d Per ? Binary period if available
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Note (1): Carbon-Enhanced Metal-Poor classes defined in table1
(stars without a measurement for Ba or Eu abundance are classified
as "Other CEMP" stars):
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Class Criteria Origin of carbon n-capture elements
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MP [Fe/H]>-2.5, [C/Fe]<0.7 supernovae r-process dominant
EMP [Fe/H]≤-2.5, [C/Fe]<0.7 supernovae r-process dominant
C-rich [Fe/H]>-2.5, [C/Fe]≥0.7,
[Ba/Fe]≥0.5, [Eu/Ba] < -0.2 TDU (3rd Dredge-Up) s-process dominant
CEMP-s [Fe/H]≤-2.5, [C/Fe]≥0.7,
[Ba/Fe]≥0.5, [Eu/Ba] < -0.2 He-FDDM* w/wo TDU s-process dominant
CEMP-nos [Fe/H]≤-2.5, [C/Fe]≥0.7,
[Ba/Fe]<0.5 TDU or unknown r-process dominant
NEMP [C/N]≲-1, [C+N/H]≳-2,
[C/Fe]≳0.5 He-FDDM* and/or TDU depending on stars
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(*) FDDM = Flash Driven Deep Mixing
Note (2): Dominant source for neutron-capture elements following Table 1.
If Eu abundance is not available, s- and r-dominance is judged by
[Ba/Fe]≥ and <0.5, respectively
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History:
From electronic version of the journal
References:
Suda et al., Paper I 2008PASJ...60.1159S 2008PASJ...60.1159S
(End) Patricia Vannier [CDS] 26-Sep-2011