J/A+A/488/943 Abundances of giants in four Galactic clusters (Sestito+, 2008)
Old open clusters as key tracers of Galactic chemical evolution.
III. Element abundances Berkeley 20, Berkeley 29, Collinder 261 and Melotte 66.
Sestito P., Bragaglia A., Randich S., Pallavicini R., Andrievsky S.M.,
Korotin S.A.
<Astron. Astrophys. 488, 943 (2008)>
=2008A&A...488..943S 2008A&A...488..943S
ADC_Keywords: Clusters, open ; Stars, giant ; Abundances
Keywords: stars: abundances - stars: evolution - Galaxy: disk -
Galaxy: open clusters and associations: general -
open clusters and associations: individual:
Berkeley 20, Berkeley 29, Collinder 261, Melotte 66
Abstract:
To constrain the formation and chemical evolution of the Galactic
disk, we surveyed open clusters of different ages, metal contents, and
distances form the Galactic centre.
We employed FLAMES on VLT-UT2 to collect UVES spectra of bright giant
stars in each of the selected clusters, and used them to derive the
iron abundance and the detailed chemical composition. Equivalent
widths were measured and abundance analysis was performed using the
MOOG code and Kurucz model atmospheres.
We derived the abundance of Fe for Mg, Al, Ca, Si, Ti, Cr, Ni, and Ba.
We employed direct line profile fitting to derive non-LTE Na
abundances. We found [Fe/H]=-0.30, -0.31, +0.13, -0.33 for Be 20,
Be 29, Cr 261, and Melotte 66, respectively (with rms values of 0.02
to 0.05dex). Alpha- and Fe-peak elements have solar ratios, Ba is
enhanced, and Na has solar ratios, suggesting that treatment of
non-LTE is very important. We confirm the presence of a metallicity
gradient in the inner disk, and a flattening in the outer part.
Description:
Spectra for 2 to 6 giant stars in Be 20, Be 29, Cr 261, and Mel 66
were obtained with FLAMES@VLT using the fiber link to UVES. Abundances
of Fe, Na, Mg, Al, Si, Ca, Ti, Cr, Ni and Ba were derived using
equivalent widths (and synthesis for Na), model atmospheres and input
atmospheric parameters based on photometry.
For each member star in the four clusters we give the measured EWs.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 91 21 Star positions, photometry and radial velocities
ew.dat 32 6482 Equivalent widths
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See also:
J/A+A/480/79 : Abundances of giants in five Galactic clusters (Bragaglia+ 2008)
Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Cluster Cluster name (1)
8- 11 I4 --- Star Star number within cluster
12- 23 A12 --- Name Star name
25- 26 I2 h RAh Right ascension (J2000)
28- 29 I2 min RAm Right ascension (J2000)
31- 36 F6.3 s RAs Right ascension (J2000)
38 A1 --- DE- Declination sign (J2000)
39- 40 I2 deg DEd Declination (J2000)
42- 43 I2 arcmin DEm Declination (J2000)
45- 50 F6.3 arcsec DEs Declination (J2000)
51- 56 F6.3 mag Bmag ?=- B magnitude
58- 63 F6.3 mag Vmag V magnitude
65- 70 F6.3 mag Imag I magnitude
72- 77 F6.2 km/s RV Radial velocity
79- 82 F4.2 km/s e_RV rms uncertainty on RV
84- 86 A3 --- Mm Membership notes
88- 91 I4 --- WEBDA ?=- WEBDA number
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Note (1): Origin of data as follows:
Be 20 = ID is ours, from the FLAMES pointing, based on EIS;
magnitudes from MacMinn et al. (1994AJ....107.1806M 1994AJ....107.1806M)
or from EIS photometry, aligned to it), or Andreuzzi et al.
(2008, MNRAS, subm.)
Be 29 = ID, BVI from Tosi et al. (2004MNRAS.354..225T 2004MNRAS.354..225T)
Cr 261 = ID is ours, from the FLAMES pointing, BVI private
communication (EIS data) by L. Prisinzano
Mel 66 = ID, VI from EIS data (Spano, priv. comm.) calibrated to
Kassis et al. (1997AJ....113.1723K 1997AJ....113.1723K)
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Byte-by-byte Description of file: ew.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Cluster Cluster name
8- 11 I4 --- Star Star number within cluster
14- 20 F7.2 0.1nm lambda Wavelength
22- 26 A5 --- El Element
28- 32 F5.1 0.1pm EW Equivalent width
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Acknowledgements:
Angela Bragaglia, angela.bragaglia(at)oabo.inaf.it
References:
Sestito et al., Paper I 2006A&A...458..121S 2006A&A...458..121S
Bragaglia et al., Paper II 2008A&A...480...79B 2008A&A...480...79B, Cat. J/A+A/480/79
(End) Patricia Vannier [CDS] 06-Jul-2008