J/AJ/132/137 Abundances of extremely metal-poor carbon stars (Cohen+, 2006)
Carbon stars in the Hamburg/ESO survey: abundances.
Cohen J.G., McWilliam A., Shectman S., Thompson I., Christlieb N.,
Melendez J., Ramirez S., Swensson A., Zickgraf F.-J.
<Astron. J., 132, 137-160 (2006)>
=2006AJ....132..137C 2006AJ....132..137C
ADC_Keywords: Stars, nearby ; Stars, carbon ; Abundances, peculiar ;
Equivalent widths
Keywords: Galaxy: halo - stars: abundances - stars: carbon
Abstract:
We have carried out a detailed abundance analysis using
high-dispersion spectra from HIRES at Keck for a sample of 16 carbon
stars found among candidate extremely metal-poor (EMP) stars from the
Hamburg/ESO Survey (HES). We find that the Fe metallicities for the
cooler C stars (Teff∼5100K) have been underestimated by a factor of 10
by the standard HES tools. The results presented here provided crucial
supporting data used recently by Cohen et al. (2005ApJ...633L.109C 2005ApJ...633L.109C) to
derive the frequency of C stars among EMP stars.
Description:
Observations with HIRES at the Keck I telescope were obtained during
several runs from 2001 September to 2005 June.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 76 17 The Sample of C Stars Selected as EMP Candidates
from the HES, Mostly from the Palomar Sample
tables.dat 48 1860 Equivalent Widths of for 15 stars of the
Primary Sample of C-Stars from the HES
(tables 3-5 of the paper)
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See also:
J/ApJS/155/651 : Evolution of extremely metal-poor stars (Herwig+, 2004)
J/AJ/128/2402 : Extremely metal-poor star candidates abundances (Lai+, 2004)
J/A+A/403/1105 : Extremely metal-poor giants equivalent widths (Francois+ 2003)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Star name
13 A1 --- n_Name [egh] Individual note on Name (1)
15- 16 I2 h RAh Right ascension (J2000)
18- 19 I2 min RAm Right ascension (J2000)
21- 24 F4.1 s RAs Right ascension (J2000)
26 A1 --- DE- Declination sign (J2000)
27- 28 I2 deg DEd Declination (J2000)
30- 31 I2 arcmin DEm Declination (J2000)
33- 34 I2 arcsec DEs Declination (J2000)
36- 41 F6.3 mag Vmag V magnitude (from ANDICAM image)
43- 48 F6.3 mag Imag ?=- I magnitude (from ANDICAM image)
50- 61 F12.4 d JD ? Julian date
62 A1 --- n_JD [c] c: see Cohen et al. (2004ApJ...612.1107C 2004ApJ...612.1107C)
63- 68 F6.1 km/s HRV ? Heliocentric radial velocity
69 A1 --- n_HRV [df] Individual note on HRV (2)
71- 75 F5.2 --- [Fe/H] ? HES metallicity
76 A1 --- EW [*] stars having equivalent widths data
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Note (1): Notes as follows:
e = Rediscovery of CS 22183-015
g = HIRES spectrum obtained too late for analysis here.
C star with very strong Ba II lines.
h = Rediscovery of CS 22957-027
Note (2): Notes as follows:
d = Double-lined spectroscopic binary, HRV variable
f = Only from the Mg triplet lines
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Byte-by-byte Description of file: tables.dat
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Bytes Format Units Label Explanations
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1- 12 A12 --- Name Star name
13 A1 --- n_EW [a] Note for HE 0012-1441 EW (1)
15- 21 F7.2 0.1nm Wave Line wavelength
23- 27 A5 --- Ion Species identification
29 A1 --- f_Ion [b] Flag on Species (2)
31- 34 F4.2 eV ExPot Excitation potential
36- 41 F6.3 [-] log(gf) Log of the oscillator strength
43 A1 --- l_EW Limit flag on EW
44- 48 F5.1 10-13m EW ? Equivalent width
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Note (1): Equivalent widths given as a guide. Synthesis used throughout
for this binary star. See text.
Note (2): Synthesis used to derive Pb abundance.
Equivalent widths given as a guidance to line strength.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 31-Aug-2007