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J/A+A/515/A28   Abundances of dwarfs and giants in 2 open clusters (Pace+, 2010)

Abundances and physical parameters for stars in the open clusters NGC 5822 and IC 4756. Pace G., Danziger J., Carraro G., Melendez J., Francois P., Matteucci F., Santos N.C. <Astron. Astrophys. 515, A28 (2010)> =2010A&A...515A..28P
ADC_Keywords: Clusters, open ; Stars, dwarfs ; Stars, giant ; Abundances ; Equivalent widths ; Spectroscopy Keywords: open clusters and associations: individual: NGC 5822 - open clusters and associations: individual: IC 4756 - stars: abundances - stars: rotation Abstract: It has been suggested that the classical chemical analysis may be affected by systematic errors that would introduce abundance differences between dwarfs and giants. For some elements, the abundance difference could be real. We address the issue by observing 2 solar-type dwarfs in NGC 5822 and 3 in IC 4756, and comparing their composition with that of 3 giants in either of the aforementioned clusters. We determine iron abundance and stellar parameters for dwarf stars. Then, abundances of calcium, sodium, nickel, titanium, aluminium, chromium, and silicon were determined for both giants and dwarfs. The standard equivalent width analysis was performed differentially with respect to the Sun. We find an iron abundance for dwarf stars equal to solar to within the margins of error for IC 4756, and slightly above for NGC 5822 ([Fe/H]=0.01 and 0.05dex respectively). We show that, for sodium, silicon, and titanium, abundances of giants are significantly higher than those of the dwarfs of the same cluster (about 0.15, 0.15, and 0.35dex). Other elements may also undergo some enhanced, but all within 0.1dex. Description: The table contains equivalent width measurements for each individual line of the adopted line list, and the corresponding abundance measurement. The data analysed consist of UVES@VLT spectra of 5 dwarf and 6 giants members of NGC 5822 and IC 4756. The resolution is of about R=100000 in the red arm, which covers the range from 4800 to 6800Å, which include all the lines analysed. The S/N is of about 100 for dwarfs, about 60 only for TATM 11003, and about 150 for giants. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file stars.dat 88 11 List of stars studied table2.dat 36 1468 Equivalent widths and abundances from individual lines
Byte-by-byte Description of file: stars.dat
Bytes Format Units Label Explanations
1- 12 A12 --- Name Star name, as used in table2 (1) 17- 37 A21 --- SName Simbad name 43- 44 I2 h RAh Simbad Hour of Right Ascension (J2000.0) 46- 47 I2 min RAm Simbad Minute of Right Ascension (J2000.0) 49- 53 F5.2 s RAs Simbad Second of Right Ascension (J2000.0) 54 A1 --- DE- Simbad Sign of the Declination (J2000.0) 55- 56 I2 deg DEd Simbad Degree of Declination (J2000.0) 58- 59 I2 arcmin DEm Simbad Arcminute of Declination (J2000.0) 61- 64 F4.1 arcsec DEs Simbad Arcsecond of Declination (J2000.0) 66- 70 F5.2 mag Bmag Simbad B band magnitude 72- 76 F5.2 mag Vmag Simbad V band magnitude 79- 82 I4 K Teff Effective temperature (from spectroscopy) 85- 88 F4.2 [cm/s2] logg Gravity
Note (1): Used names: * HER = Herzog and Sanders (1975A&AS...19..211H) (dwarfs) * TATM = Twarog, Anthony-Twarog and McClure (1993PASP..105...78T) (dwarfs) * IC5746No = Kopff (1943AN....274...69K) (giants) * NGC5822No = Bozkurt (1974RMxAA...1...89B) (giants)
Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 12 A12 --- Name Star name, as in "stars.dat" file 14- 20 F7.2 0.1nm lambda Line wavelength 22- 24 A3 --- Ion Element and ionization stage 26- 30 F5.1 0.1pm EW Line equivalent width 32- 36 F5.2 [Sun] [X/H] Abundance relative to the Sun
Acknowledgements: Giancarlo Pace, gpace(at)astro.up.pt
(End) Giancarlo Pace [CAUP, Portugal], Patricia Vannier [CDS] 12-Feb-2010
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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