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J/A+A/464/927       Abundances of red giants in NGC 6752       (Carretta+, 2007)

Na-O Anticorrelation and HB. II. The Na-O anticorrelation in the globular cluster NGC 6752 Carretta E., Bragaglia A., Gratton R.G., Lucatello S., Momany Y. <Astron. Astrophys. 464, 927 (2007)> =2007A&A...464..927C
ADC_Keywords: Clusters, globular ; Stars, population II ; Abundances ; Radial velocities Keywords: stars: abundances - stars: atmospheres - stars: Population II - Galaxy: globular clusters: general - Galaxy: globular clusters: individual: NGC 6752 Abstract: We are studying the Na-O anticorrelation in several globular clusters of different Horizontal Branch (HB) morphology in order to derive a possible relation between (primordial) chemical inhomogeneities and morphological parameters of the cluster population. We used the multifiber spectrograph FLAMES on the ESO Very Large Telescope UT2 and derived atmospheric parameters and elemental abundances of Fe, O and Na for about 150 red giant stars in the Galactic globular cluster NGC 6752. The average metallicity we derive is [Fe/H]=-1.56, in agreement with other results from red giants, but lower than obtained for dwarfs or early subgiants. In NGC 6752 there is not much space for an intrinsic spread in metallicity: on average, the rms scatter in [Fe/H] is 0.037±0.003dex, while the scatter expected on the basis of the major error sources is 0.039±0.003dex. The distribution of stars along the Na-O anticorrelation is different to what was found in the first paper of this series for the globular cluster NGC 2808: in NGC 6752 it is skewed toward more Na-poor stars, and it resembles more the one in M 13. Detailed modeling is required to clarify whether this difference may explain the very different distributions of stars along the HB. Description: Spectra for 151 RGB stars in NGC 6752 were obtained with FLAMES@VLT using two gratings (HR11, HR13). Abundances of Fe, O, Na were derived using equivalent widths, model atmospheres and atmospheric parameters based on photometry. For each star we give identification, equatorial coordinates, VBJK magnitudes, S/N, heliocentric radial velocity for both gratings, Teff, logg, [A/H], vt, [Fe/H], [O/Fe], [Na/Fe]. Equivalent widths are given in tablea. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 88 151 Identification, equatorial coordinates, VBJK magnitudes, S/N, heliocentric radial velocity table3.dat 54 137 Atmospheric parameters and iron abundance table5.dat 37 137 O and Na abundances tablea.dat 37 8220 Equivalent widths for 137 objects
See also: J/A+A/455/271 : Abundances of red giants in NGC 6441 (Gratton+, 2006) J/A+A/464/939 : Abundances of red giants in NGC 6218 (Carreta+, 2007) J/A+A/464/953 : Abundances of red giants in NGC 6441 (Gratton+, 2007) J/A+A/464/967 : Abundances of red giants in NGC 6388 (Carreta+, 2007) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
2- 6 I5 --- ID Identification (from Momany et al., 2004A&A...420..605M) 8- 9 I2 h RAh Right ascension (J2000.0) 11- 12 I2 min RAm Right ascension (J2000.0) 14- 19 F6.3 s RAs Right ascension (J2000.0) 21 A1 --- DE- Declination sign (J2000.0) 22- 23 I2 deg DEd Declination (J2000.0) 25- 26 I2 arcmin DEm Declination (J2000.0) 28- 32 F5.2 arcsec DEs Declination (J2000.0) 34- 39 F6.3 mag Vmag ? Johnson V magnitude 41- 46 F6.3 mag Bmag ? Johnson B magnitude 48- 53 F6.3 mag Jmag ? 2MASS J magnitude 55- 60 F6.3 mag Kmag ? 2MASS J magnitude 62- 64 I3 --- S/N Signal-to-Noise ratio 66- 71 F6.2 km/s HRV11 ? Heliocentric radial velocity for grating HR11 73- 78 F6.2 km/s HRV13 ? Heliocentric radial velocity for grating HR13 80- 84 A5 --- HR [11,13 ] Grating(s) used 86- 88 A3 --- Flag [F*+, ] Notes (1)
Note (1): Notes as follows: F = field star * = stars with unreliable V-K + = not used in analysis
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
2- 6 I5 --- ID Identification (from Momany et al., 2004A&A...420..605M) 8- 11 I4 K Teff Effective temperature 13- 16 F4.2 [cm/s2] logg Gravity 18- 22 F5.2 [Sun] [A/H] Metallicity 24- 27 F4.2 km/s Vt Microturbulent velocity 29- 30 I2 -- o_FeI Number of lines of Fe I 32- 36 F5.2 [Sun] [Fe/H]I Average star [Fe/H]I 38- 41 F4.2 [Sun] e_[Fe/H]I rms uncertainty on [Fe/H]I 43 I1 -- o_FeII ? Number of lines of Fe II 45- 49 F5.2 [Sun] [Fe/H]II ? Average star [Fe/H]II 51- 54 F4.2 [Sun] e_[Fe/H]II ? rms uncertainty on [Fe/H]II
Byte-by-byte Description of file: table5.dat
Bytes Format Units Label Explanations
2- 6 I5 --- ID Identification (from Momany et al., 2004A&A...420..605M) 8 I1 --- o_O ? Number of lines of O 10- 14 F5.2 [Sun] [O/Fe] ? Average [O/Fe] 16- 19 F4.2 [Sun] e_[O/Fe] ? rms uncertainty on [O/Fe] 22 I1 --- o_Na ? Number of lines of Na 24- 28 F5.2 [Sun] [Na/Fe] ? Average [Na/Fe] 30- 33 F4.2 [Sun] e_[Na/Fe] ? rms uncertainty on [Na/Fe] 35 I1 --- Flag1 [1/3] Flag for grating (1) 37 I1 -- Flag2 [0/1] Flag for measure/limit for O (2)
Note (1): Flags for grating as follows: 1 = HR13 only 2 = both HR11 & HR13 3 = only HR11 Note (2): Flags for measure/limit for O as follows: 0 = O upper limit 1 = O measured
Byte-by-byte Description of file: tablea.dat
Bytes Format Units Label Explanations
1- 5 I5 ---- ID Identification (from Momany et al., 2004A&A...420..605M) 7- 10 F4.1 --- --- Atomic number and ionization stage (1) 13- 19 F7.2 0.1nm lambda Wavelength 21- 24 F4.2 eV EP Excitation potential 26- 31 F6.2 [cm/s2] loggf Surface gravity 33- 37 F5.1 0.1pm EW Equivalent width
Note (1): NN.1 for neutral, NN.2 for singly ionized
Acknowledgements: Eugenio Carretta, eugenio.carretta(at)oabo.inaf.it References: Carreta et al., Paper I, NGC 2808 2006A&A...450..523C Gratton et al., Paper III, NGC 6441 2006A&A...455..271G, Cat. J/A+A/455/271 Carreta et al., Paper IV, NGC 6218 2007A&A...464..939C, Cat. J/A+A/464/939 Gratton et al., Paper V, NGC 6441 2007A&A...464..953G, Cat. J/A+A/464/953 Carreta et al., Paper VI, NGC 6388 2007A&A...464..967C, Cat. J/A+A/464/967
(End) Patricia Vannier [CDS] 22-Feb-2007
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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