J/A+A/585/A150 On the metallicity of open clusters. III. (Netopil+, 2016)
On the metallicity of open clusters. III. Homogenised sample.
Netopil M., Paunzen E., Heiter U., Soubiran C.
<Astron. Astrophys., 585, A150-150 (2016)>
=2016A&A...585A.150N 2016A&A...585A.150N (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Abundances, [Fe/H]
Keywords: Galaxy: abundances - Galaxy: structure -
open clusters and associations: general
Abstract:
Open clusters are known as excellent tools for various topics in
Galactic research. For example, they allow accurately tracing the
chemical structure of the Galactic disc. However, the metallicity is
known only for a rather low percentage of the open cluster population,
and these values are based on a variety of methods and data.
Therefore, a large and homogeneous sample is highly desirable. In the
third part of our series we compile a large sample of homogenised open
cluster metallicities using a wide variety of different sources. These
data and a sample of Cepheids are used to investigate the radial
metallicity gradient, age effects, and to test current models. We used
photometric and spectroscopic data to derive cluster metallicities.
The different sources were checked and tested for possible offsets and
correlations. In total, metallicities for 172 open cluster were
derived. We used the spectroscopic data of 100 objects for a study of
the radial metallicity distribution and the age-metallicity relation.
We found a possible increase of metallicity with age, which, if
confirmed, would provide observational evidence for radial migration.
Although a statistical significance is given, more studies are
certainly needed to exclude selection effects, for example. The
comparison of open clusters and Cepheids with recent Galactic models
agrees well in general. However, the models do not reproduce the flat
gradient of the open clusters in the outer disc. Thus, the effect of
radial migration is either underestimated in the models, or an
additional mechanism is at work. Apart from the Cepheids, open
clusters are the best tracers for metallicity over large
Galactocentric distances in the Milky Way. For a sound statistical
analysis, a sufficiently large and homogeneous sample of cluster
metallicities is needed. Our compilation is currently by far the
largest and provides the basis for several basic studies such as the
statistical treatment of the Galactic cluster population, or
evolutionary studies of individual star groups in open clusters.
Description:
In Paper II (Heiter et al., Paper II 2014A&A...561A..93H 2014A&A...561A..93H) we have
evaluated available spectroscopic iron abundance determinations of
open cluster stars and presented mean values for 78 open clusters. The
results are based on high-resolution data (R≥25000) with high
signal-to-noise ratios (S/N≥50). Furthermore, quality criteria
were introduced by adopting only [Fe/H] measurements of stars with
Teff=4400-6500K and logg≥2.0dex. We have to note that
the mean iron abundance for Berkeley 29, listed in Paper II, also
incorporates some measurements based upon lower S/N data. In the
present paper we therefore list the correct values for the higher and
lower quality data. Since publication of Paper II, some new studies
were made (Boesgaard et al., 2013ApJ...775...58B 2013ApJ...775...58B; Bocek Topcu et al.,
2015, Cat. J/MNRAS/446/3562; Carraro et al., 2014A&A...568A..86C 2014A&A...568A..86C;
Donati et al., 2015, Cat. J/MNRAS/446/1411; Magrini et al..
2014A&A...563A..44M 2014A&A...563A..44M, 2015A&A...580A..85M 2015A&A...580A..85M; Molenda-Zakowicz et al.,
2014MNRAS.445.2446M 2014MNRAS.445.2446M; Monaco et al., 2014A&A...564L...6M 2014A&A...564L...6M; Reddy et al.,
2015MNRAS.450.4301R 2015MNRAS.450.4301R), which we examined the same way as described in
Paper II. This adds ten open clusters to our list (Berkeley 81,
NGC 1342, NGC 1662, NGC 1912, NGC 2354, NGC 4337, NGC 4815, NGC 6811,
Trumpler 5, and Trumpler 20) and supplementary data for NGC 752,
NGC 2447, NGC 2632, and NGC 6705.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 92 172 Metallicities of the open clusters
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See also:
J/A+A/561/A93 : On the metallicity of open clusters. II. (Heiter+, 2014)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 13 A13 --- Cluster Cluster name
15- 19 F5.2 [-] [Fe/H]HQS ? Metallicity from high-quality spectroscopic
data data (HQS)
21- 24 F4.2 [-] e_[Fe/H]HQS ? rms uncertainty on [Fe/H]HQS
26- 27 I2 --- N[Fe/H]HQS ? Number of stars used for the calculation
of [Fe/H]HQS
29- 33 F5.2 [-] [Fe/H]LQS ? Metallicity from low-quality spectroscopic
data data (LQS)
35- 38 F4.2 [-] e_[Fe/H]LQS ? rms uncertainty on [Fe/H]LQS
40- 42 I3 --- N[Fe/H]LQS ? Number of stars used for the calculation
of [Fe/H]LQS
44- 48 F5.2 [-] [Fe/H]Phot ? Metallicity from photometry
50- 53 F4.2 [-] e_[Fe/H]Phot ? rms uncertainty on [Fe/H]Phot
55- 58 F4.2 --- w_[Fe/H]Phot ? Total weight of the photometric metallicities
60- 68 A9 --- Systems Code for the photometric systems (1)
70- 74 F5.2 kpc RGC Mean distance from the Sun
76- 79 F4.2 kpc e_RGC rms uncertainty on RGC
81- 84 F4.2 Gyr Age Age
86- 89 F4.2 Gyr e_Age rms uncertainty on Age
91- 92 I2 --- N Number of studies used to calculate the mean
distance from the Sun and the age of the
open cluster
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Note (1): The code for the photometric systems is as follows:
1 = DG
2 = DDO
3 = Friel
4 = Ca II
5 = Stromgren
6 = Caby
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History:
From electronic version of the journal
References:
Paunzen et al., Paper I 2010A&A...517A..32P 2010A&A...517A..32P
Heiter et al., Paper II 2014A&A...561A..93H 2014A&A...561A..93H, Cat. J/A+A/561/A93
(End) Patricia Vannier [CDS] 10-Mar-2016