J/AJ/130/2804 Carbon abundances in metal-poor stars (Rossi+, 2005)
Estimation of carbon abundances in metal-poor stars.
I. Application to the strong G-band stars of Beers, Preston, and Shectman.
Rossi S., Beers T.C., Sneden C., Sevastyanenko T., Rhee J., Marsteller B.
<Astron. J., 130, 2804-2823 (2005)>
=2005AJ....130.2804R 2005AJ....130.2804R
ADC_Keywords: Abundances ; Stars, carbon ; Stars, metal-deficient
Keywords: abundances - stars: carbon - stars: Population II -
techniques: spectroscopic
Abstract:
We develop and test a method for the estimation of metallicities
([Fe/H]) and carbon abundance ratios ([C/Fe]) for carbon-enhanced
metal-poor (CEMP) stars based on the application of artificial neural
networks, regressions, and synthesis models to medium-resolution
(1-2Å) spectra and J-K colors. We calibrate this method by
comparison with metallicities and carbon abundance determinations for
118 stars with available high-resolution analyses reported in the
recent literature.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 65 119 Photometric information for calibration stars
table3.dat 78 119 Spectroscopic observations, and adopted abundance
and model parameters for calibration stars
refs.dat 120 24 References
table4.dat 96 119 Estimates of [Fe/H] and [C/Fe] from artificial
neural networks, regression, and synthesis for
calibration stars
table6.dat 65 56 *Photometric information for BPSII "Strong G-Band"
stars
table7.dat 87 56 *Spectroscopic observations, derived abundances, and
model parameters for BPSII "Strong G-Band" stars
--------------------------------------------------------------------------------
Note on table6.dat and table7.dat: BPSII stands for Beers et al., 1992,
Cat. J/AJ/103/1987
--------------------------------------------------------------------------------
See also:
J/AJ/103/1987 : Stars of very low metal abundance (Beers+ 1992)
J/A+A/354/169 : Metal-poor field stars abundances (Gratton+, 2000)
J/A+A/356/238 : Atmospheric parameters in metal-poor stars. III.
(Carretta+ 2000)
J/A+A/375/366 : Carbon stars from the Hamburg/ESO survey (Christlieb+ 2001)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Star name
14- 18 F5.2 mag Vmag The V band magnitude
20- 23 F4.2 mag B-V The (B-V) color index
25- 30 F6.3 mag Jmag 2MASS J band magnitude
32- 36 F5.3 mag e_Jmag Uncertainty in Jmag
38- 42 F5.3 mag J-K 2MASS (J-K) color index
44- 48 F5.3 mag e_J-K Uncertainty in J-K
50- 54 F5.3 mag E(B-V) The adopted E(B-V) color excess
56- 59 F4.2 mag (B-V)0 The intrinsic (B-V) color index
61- 65 F5.3 mag (J-K)0 The intrinsic (J-K) color index
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Star name
14- 21 A8 --- Tel Telescope(s) used in the observation (G1)
23- 27 F5.2 0.1nm KP The KP line index (G2)
29- 32 F4.2 0.1nm GP The GP line index (G3)
34- 38 F5.2 [Sun] [Fe/H] Adopted [Fe/H] from literature
40- 44 F5.2 [Sun] [C/H] Adopted [C/H] from literature
46- 50 F5.2 [Sun] [C/Fe] Adopted [C/Fe] from literature
52- 60 A9 --- Ref Reference source(s) (detailed in refs.dat)
62- 65 I4 K Teff Model effective temperature (1)
67- 69 F3.1 [cm/s2] log(g) Model log surface gravity (1)
71- 74 F4.1 [Sun] M[Fe/H] Model [Fe/H] (1)
76- 78 F3.1 km/s xi Microturbulence velocity (1)
--------------------------------------------------------------------------------
Note (1): The model parameters listed are those adopted based on the literature
sources listed. For consistency of the spectral synthesis modeling
with the predicted [C/Fe] for the BPSII "Strong G-Band" stars in
Table 7, we used an input microturbulence value of 2.0km/s for
estimation of the [C/Fe]S values reported in this table.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: refs.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Ref Reference number
4- 22 A19 --- Bibcode Bibcode
24- 48 A25 --- Aut Author's name
50-120 A71 --- Comm Comment
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Name Star name
14- 18 F5.2 [Sun] [Fe/H] Adopted [Fe/H]
20- 24 F5.2 [Sun] [Fe/H]A Derived artificial neural network analysis
[Fe/H]
26- 30 F5.2 [Sun] res[Fe/H]A Residual in derived [Fe/H]A
32- 36 F5.2 [Sun] [Fe/H]R ? Derived regression analysis [Fe/H]
38- 42 F5.2 [Sun] res[Fe/H]R ? Residual in derived [Fe/H]R
44- 48 F5.2 [Sun] [C/Fe] Adopted external [C/Fe] estimate
from the literature
50- 54 F5.2 [Sun] [C/Fe]A Derived analysis [C/Fe]
56- 60 F5.2 [Sun] res[C/Fe] Residual in derived [C/Fe]A
62- 66 F5.2 [Sun] [C/Fe]R Derived regression analysis [C/Fe]
68- 72 F5.2 [Sun] res[C/Fe]R Residual in derived [C/Fe]R
74 I1 --- B-Teff [1/4] Calibration star groupings in effective
temperature bin (1)
76 I1 --- B-Fe/H [1/4] Calibration star groupings in [Fe/H]
bin (2)
78 I1 --- B-C/Fe [1/4] Calibration star groupings in [C/Fe]
bin (3)
80 A1 --- l_[C/Fe]S Limit flag on [C/Fe]S
82- 86 F5.2 [Sun] [C/Fe]S Spectral synthesis estimate of [C/Fe]
87- 88 A2 --- u_[C/Fe]S [ :] Uncertainty flag on [C/Fe]S (4)
90- 94 F5.2 [Sun] res[C/Fe]S ? Residual in [C/Fe]S
96 A1 --- f_Name [X] Indicates star not used in calibration of
the ANNs or regression estimates of [C/Fe]
--------------------------------------------------------------------------------
Note (1): Calibration star groupings in Teff bin, defined as follows:
1 = Teff>5500K;
2 = 5000K<Teff≤5500K;
3 = 4500K<Teff≤5000K;
4 = Teff≤4500K.
Note (2): Calibration star groupings in [Fe/H] bin, defined as follows:
1 = [Fe/H]>-1.0;
2 = -2.0<[Fe/H]≤-1.0;
3 = -3.0<[Fe/H]≤-2.0;
4 = [Fe/H]≤-3.0.
Note (3): Calibration star groupings in [C/Fe] bin, defined as follows:
1 = [C/Fe]>+1.0;
2 = +0.50<[C/Fe]≤+1.0;
3 = 0.0≤[C/Fe]≤+0.5;
4 = [C/Fe]≤0.0.
Note (4): Uncertainty flag on [C/Fe]S, defined as follows:
: = uncertain;
:: = highly uncertain.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- --- [CS]
4- 12 A9 --- BPS-CS Star name (BPS CS NNNNN-NNN in Simbad)
14- 18 F5.2 mag Vmag ? The V band magnitude
20- 23 F4.2 mag B-V ? The (B-V) color index
25- 30 F6.3 mag Jmag ? The J band magnitude
32- 36 F5.3 mag e_Jmag ? Uncertainty in Jmag
38- 42 F5.3 mag J-K ? The (J-K) color index
44- 48 F5.3 mag e_J-K ? Uncertainty in J-K
50- 54 F5.3 mag E(B-V) The (B-V) color excess
56- 59 F4.2 mag (B-V)0 ? The intrinsic (B-V) color index
61- 65 F5.3 mag (J-K)0 ? The intrinsic (J-K) color index
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table7.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- --- [CS]
4- 12 A9 --- BPS-CS Star name (BPS CS NNNNN-NNN in Simbad)
14- 17 A4 --- Tel Telescope used in the observation (G1)
19- 22 F4.2 --- KP The KP line index (G2)
24- 27 F4.2 --- GP The GP line index (G3)
29- 33 F5.2 [Sun] [Fe/H]A ? Log of the artificial neural network
analysis Fe/H abundance estimate
35- 39 F5.2 [Sun] [Fe/H]R ? Log of the regression analysis Fe/H
abundance
41- 45 F5.2 [Sun] [C/Fe]A Log of the artificial neural network analysis
C/Fe abundance estimate
46- 47 A2 --- u_[C/Fe]A [ :] Uncertainty flag on [C/Fe]A (2)
49- 53 F5.2 [Sun] [C/Fe]R Log of the regression analysis C/Fe abundance
54- 55 A2 --- u_[C/Fe]R [ :] Uncertainty flag on [C/Fe]R (2)
57- 60 I4 K Teff ? Model effective temperature
62- 64 F3.1 [cm/s2] log(g) ? Model log surface gravity
66- 69 F4.1 [Sun] M[Fe/H] ? Model log of the Fe/H number abundance
71- 73 F3.1 km/s xi ? Microturbulence velocity
75- 79 F5.2 [Sun] [C/Fe]S ? Log of the spectral synthesis estimate of
C/Fe abundance
80- 81 A2 --- u_[C/Fe]S [ :] Uncertainty flag on [C/Fe]S (2)
83- 87 F5.2 [Sun] [C/Fe]F Log of the final adopted [C/Fe] abundance
--------------------------------------------------------------------------------
Note (2): Uncertainty flag on [C/Fe]S, defined as follows:
: = uncertain;
:: = highly uncertain.
--------------------------------------------------------------------------------
Global Notes:
Note (G1): Telescope(s) used in the observation, defined as follows:
A = Anglo Australian 3.8m telescope;
C = CTIO 4m telescope;
K = KPNO 4m telescope;
I = Isaac Newton 2.5m telescope;
L = Las Campanas 2.5m telescope;
M = McDonald Observatory 2.7m telescope;
P = Palomar 5m telescope;
c = CTIO 1.5m telescope;
e = ESO 1.5m telescope;
k = KPNO 2.1m telescope;
s = SSO 2.3m telescope.
Note (G2): The KP line index is a pseudo-equivalent width measure of the
CaII K line (around 393nm).
Note (G3): The GP line index is a fixed 15Å wide-band measure of the
strength of the CH G band (around 430nm)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Marianne Brouty [CDS] 18-Jul-2006