J/ApJ/689/1031 Heavy element abundances in giant stars (Yong+, 2008)
Heavy element abundances in giant stars of the globular clusters M4 and M5.
Yong D., Karakas A.I., Lambert D.L., Chieffi A., Limongi M.
<Astrophys. J., 689, 1031-1043 (2008)>
=2008ApJ...689.1031Y 2008ApJ...689.1031Y
ADC_Keywords: Equivalent widths ; Abundances ; Stars, giant ; Clusters, globular
Keywords: Galaxy: abundances - globular clusters: individual (M4, M5) -
stars: abundances
Abstract:
We present a comprehensive abundance analysis of 27 heavy elements in
bright giant stars of the globular clusters M4 and M5 based on
high-resolution, high signal-to-noise ratio spectra obtained with the
Magellan Clay Telescope. We confirm and expand on previous results for
these clusters by showing that (1) all elements heavier than, and
including, Si have constant abundances within each cluster, (2) the
elements from Ca to Ni have indistinguishable compositions in M4 and
M5, (3) Si, Cu, Zn, and all s-process elements are approximately
0.3dex overabundant in M4 relative to M5, and (4) the r-process
elements Sm, Eu, Gd, and Th are slightly overabundant in M5 relative
to M4. The cluster-to-cluster abundance differences for Cu and Zn are
intriguing, especially in light of their uncertain nucleosynthetic
origins. We confirm that stars other than Type Ia supernovae must
produce significant amounts of Cu and Zn at or below the clusters'
metallicities. If intermediate-mass AGB stars or massive stars are
responsible for the Cu and Zn enhancements in M4, the similar [Rb/Zr]
ratios and (preliminary) Mg isotope ratios in both clusters may be
problematic for either scenario. For the elements from Ba to Hf, we
assume that the s- and r-process contributions are scaled versions of
the solar s- and r-process abundances. We quantify the relative
fractions of s- and r-process material for each cluster and show that
they provide an excellent fit to the observed abundances.
Description:
The sample consists of 12 bright giants in M4 and 2 bright giants in
M5 observed with the high-resolution spectrograph MIKE on the Magellan
Clay Telescope on 2004 June 12-13, July 16, and July 18. These are the
same high-quality spectra analyzed by Yong et al.
(2008ApJ...673..854Y 2008ApJ...673..854Y; R=55000, wavelength coverage from 3800 to
8500Å, and S/N=140 per resolution element at 4000Å and S/N=800
per resolution element at 7800Å).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 29 14 Stellar parameters from Yong et al.
(2008ApJ...673..854Y 2008ApJ...673..854Y)
table2.dat 46 1162 Equivalent widths
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See also:
J/A+A/490/625 : Abundances of NGC 6121 red giants (Marino+, 2008)
J/ApJS/169/120 : Transition probabilities for HfII and Hf (Lawler+, 2007)
J/ApJS/162/227 : Transition probabilities for SmII (Lawler+, 2006)
J/ApJS/167/292 : Laboratory transition probabilities for Gd II (Den Hartog+,
2006)
J/AJ/129/303 : Abundances of stars in M3 and M13 (Cohen+, 2005)
J/MNRAS/340/304 : [X/Fe] of Galactic disc F and G dwarfs (Reddy+, 2003)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 A8 --- Name Star designation
10- 13 I4 K Teff Effective temperature (1)
15- 18 F4.2 [cm/s2] logg Surface gravity (1)
20- 23 F4.2 km/s xi Microturbulent velocity (ξt) (1)
25- 29 F5.2 [-] [Fe/H] Fe/H abundance
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Note (1): We estimate that the internal errors are Teff±50K,
logg±0.2dex, and ξt±0.2km/s. For further details regarding
the observations, data reduction, and derivation of stellar
parameters, see Yong et al. (2008ApJ...673..854Y 2008ApJ...673..854Y).
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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- 8 A8 --- Name Star designation
10- 17 F8.3 0.1nm lambda Wavelength in Angstroms (Å)
19- 22 F4.1 --- Sp Species identification (1)
24- 27 F4.2 eV ExPot Excitation potential
29- 33 F5.2 [-] log(gf) Log of the oscillator strength
35- 38 A4 --- r_log(gf) Reference for log(gf) (2)
40- 44 F5.1 0.1pm EW ? Equivalent width in milli-Angstrom (mÅ)
46 A1 --- f_EW [s] synthetic EW (3)
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Note (1): In the format XX.YY where XX is the atomic number and YY is the
ionization level, e.g. 14.00=SiI.
Note (2): References as follows:
M05 = Cohen & Melendez (2005; Cat. J/AJ/129/303);
CS02 = Cunha et al. (2002AJ....124..379C 2002AJ....124..379C);
DL03 = Den Hartog et al. (2003ApJS..148..543D 2003ApJS..148..543D);
DL06 = Den Hartog et al. (2006; Cat. J/ApJS/167/292);
IK01 = Ivans et al. (1999AJ....118.1273I 1999AJ....118.1273I);
KB95 = Kurucz & Bell (1995all..book.....K 1995all..book.....K);
LD06 = Lawler et al. (2006; Cat. J/ApJS/162/227);
LH07 = Lawler et al. (2007; Cat. J/ApJS/169/120);
LUCK = R. E. Luck (priv. comm.);
ND95 = Norris et al. (1995ApJ...447..680N 1995ApJ...447..680N);
NZ02 = Nilsson et al. (2002A&A...382..368N 2002A&A...382..368N);
PN00 = Prochaska et al. (2000AJ....120.2513P 2000AJ....120.2513P);
RC02 = Ramirez & Cohen (2002AJ....123.3277R 2002AJ....123.3277R);
RT03 = Reddy et al. (2003; Cat. J/MNRAS/340/304);
SS00 = Smith et al. (2000AJ....119.1239S 2000AJ....119.1239S).
Note (3):
s = abundance determined by generating synthetic spectrum using MOOG and
adjusting the abundance to match the observed spectrum.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 24-Jan-2011