J/A+A/548/A122 Berkeley 39 stars photometry and abundances (Bragaglia+, 2012)
Searching for multiple stellar populations in the massive, old open cluster
Berkeley 39.
Bragaglia A., Gratton R.G., Carretta E., D'Orazi V., Sneden C.,
Lucatello S.
<Astron. Astrophys., 548, A122-122 (2012)>
=2012A&A...548A.122B 2012A&A...548A.122B
ADC_Keywords: Clusters, open ; Photometry ; Abundances
Keywords: stars: abundances - open clusters and associations: general -
open clusters and associations: individual: Berkeley 39 -
stars: atmospheres
Abstract:
The most massive star clusters include several generations of stars
with a different chemical composition (mainly revealed by an Na-O
anti-correlation) while low-mass star clusters appear to be chemically
homogeneous. We are investigating the chemical composition of several
clusters with masses of a few 104M☉ to establish the lower
mass limit for the multiple stellar population phenomenon. Using
VLT/FLAMES spectra we determine abundances of Fe, O, Na, and several
other elements (α Fe-peak, and neutron-capture elements) in the
old open cluster Berkeley 39. This is a massive open cluster:
M∼104M☉, approximately at the border between small globular
clusters and large open clusters. Our sample size of about 30 stars is
one of the largest to be studied for abundances in any open cluster,
and could be useful to determine improved cluster parameters, like
age, distance, and reddening, when coupled with precise,
well-calibrated photometry. We find that Berkeley 39 is slightly
metal- poor, <[Fe/H]≳=-0.20, in agreement with previous studies of
this cluster. More importantly, we do not detect any star-to-star
variation in the abundances of Fe, O, and Na, within quite stringent
upper limits. The r.m.s. scatter is of 0.04, 0.10, and 0.05dex for Fe,
O, and Na, respectively. Such a small spread can be entirely explained
by the noise in the spectra and by uncertainties in the atmospheric
parameters. We conclude that Berkeley 39 is a single-population
cluster.
Description:
We obtained six exposures of Be 39 with the multi-object spectrograph
VLT/FLAMES, as in our previous studies on the Na-O anti-correlations
in clusters.
High resolution UVES and GIRAFFE spectra have been acquired with
We measured elemental abundances and present here the EWs,
separately for the UVES and GIRAFFE stars. Based on observations
obtained under ESO Programme 386.B-0009.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 78 118 Information on the observed stars
stars.dat 38 29 List of studied stars
table3.dat 74 29 Stellar parameters, number of lines, Fe, Na,
and O abundances and errors
uves.dat 70 180 Equivalence widths for 7 stars
giraffe.dat 160 82 Equivalence widths for 22 stars
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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- 2 A2 --- Sample Sample (G1)
4- 7 I4 --- ID Identification number (G2)
9- 12 I4 --- WEBDA WEBDA identification number
14 I1 h RAh Right ascension (J2000)
16- 17 I2 min RAm Right ascension (J2000)
19- 24 F6.3 s RAs Right ascension (J2000)
26 A1 --- DE- Declination sign (J2000)
27 I1 deg DEd Declination (J2000)
29- 30 I2 arcmin DEm Declination (J2000)
32- 36 F5.2 arcsec DEs Declination (J2000)
38- 43 F6.3 mag Vmag V magnitude
45- 49 F5.3 mag B-V B-V colour index
51- 55 F5.3 mag V-I V-I colour index
57- 60 I4 --- S/N ? Signal-to-noise ratio
62- 67 F6.2 km/s RV ? Radial velocity
69- 78 A10 --- Notes Notes (2)
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Note (2): Notes as follows:
* = Friel et al. (2010, cat. J/AJ/139/1942)
a = B-V colour modified (see text)
b = V-I colour modified (see text)
bin? = binary ?
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Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- ID Star number (G2)
7- 8 I2 h RAh Right ascension (J2000)
10- 11 I2 min RAm Right ascension (J2000)
13- 17 F5.2 s RAs Right ascension (J2000)
19 A1 --- DE- Declination sign (J2000)
20- 21 I2 deg DEd Declination (J2000)
23- 24 I2 arcmin DEm Declination (J2000)
26- 30 F5.2 arcsec DEs Declination (J2000)
32- 38 A7 --- Inst Instrument used for observation (uves or giraffe)
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Sample Sample (G1)
4- 7 I4 --- ID Identification number (G2)
9- 12 I4 K Teff Effective temperature
14- 17 F4.2 [cm/s2] logg Surface gravity
19- 22 F4.2 km/s vt Microturbulent velocity
24- 25 I2 --- o_[Fe/H]I Number of lines for [Fe/H]I
27- 31 F5.2 [Sun] [Fe/H]I Abundance [Fe/H]I
33- 36 F4.2 [Sun] e_[Fe/H]I rms uncertainty on [Fe/H]I
38- 39 I2 --- o_[Fe/H]II Number of lines for [Fe/H]II
41- 45 F5.2 [Sun] [Fe/H]II Abundance [Fe/H]II
47- 50 F4.2 [Sun] e_[Fe/H]II rms uncertainty on [Fe/H]II
52- 56 F5.2 [Sun] [O/Fe] Abundance [O/Fe]
58- 61 F4.2 [Sun] e_[O/Fe] ? rms uncertainty on [O/Fe]
63 I1 --- o_[Na/Fe] Number of lines for [Na/Fe]
65- 69 F5.2 [Sun] [Na/Fe] Abundance [Na/Fe]
71- 74 F4.2 [Sun] e_[Na/Fe] rms uncertainty on [Na/Fe]
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Byte-by-byte Description of file: uves.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- Ion Element and ionisation of line
8- 14 F7.2 0.1nm lambda Wavelength of line (Å)
18- 21 F4.2 eV EP Excitation potential
23- 28 F6.2 --- loggf Oscillator strength
30- 34 F5.1 0.1pm W1256 Equivalent width of line in star 1256
36- 40 F5.1 0.1pm W1407 Equivalent width of line in star 1407
42- 46 F5.1 0.1pm W1657 Equivalent width of line in star 1657
48- 52 F5.1 0.1pm W2130 Equivalent width of line in star 2130
54- 58 F5.1 0.1pm W2144 Equivalent width of line in star 2144
60- 64 F5.1 0.1pm W2262 Equivalent width of line in star 2262
66- 70 F5.1 0.1pm W2376 Equivalent width of line in star 2376
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Byte-by-byte Description of file: giraffe.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- Ion Element and ionisation of line
8- 14 F7.2 0.1nm lambda Wavelength of line (Å)
18- 21 F4.2 eV EP Excitation potential
23- 28 F6.2 --- loggf Oscillator strength
30- 34 F5.1 0.1pm W11 Equivalent width of line in star 11
36- 40 F5.1 0.1pm W281 Equivalent width of line in star 281
42- 46 F5.1 0.1pm W537 Equivalent width of line in star 537
48- 52 F5.1 0.1pm W591 Equivalent width of line in star 591
54- 58 F5.1 0.1pm W618 Equivalent width of line in star 618
60- 64 F5.1 0.1pm W773 Equivalent width of line in star 773
66- 70 F5.1 0.1pm W802 Equivalent width of line in star 802
72- 76 F5.1 0.1pm W892 Equivalent width of line in star 892
78- 82 F5.1 0.1pm W984 Equivalent width of line in star 984
84- 88 F5.1 0.1pm W1057 Equivalent width of line in star 1057
90- 94 F5.1 0.1pm W1068 Equivalent width of line in star 1068
96-100 F5.1 0.1pm W1125 Equivalent width of line in star 1125
102-106 F5.1 0.1pm W1139 Equivalent width of line in star 1139
108-112 F5.1 0.1pm W1310 Equivalent width of line in star 1310
114-118 F5.1 0.1pm W1363 Equivalent width of line in star 1363
120-124 F5.1 0.1pm W1374 Equivalent width of line in star 1374
126-130 F5.1 0.1pm W1411 Equivalent width of line in star 1411
132-136 F5.1 0.1pm W1447 Equivalent width of line in star 1447
138-142 F5.1 0.1pm W1547 Equivalent width of line in star 1547
144-148 F5.1 0.1pm W2088 Equivalent width of line in star 2088
150-154 F5.1 0.1pm W2089 Equivalent width of line in star 2089
156-160 F5.1 0.1pm W2284 Equivalent width of line in star 2284
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Global notes:
Note (G1): Samples as follows:
UV = UVES sample
GB = GIRAFFE, bright sample
Gf = GIRAFFE faint sample
B = Binaries/not analysed
N = Non members/not analysed
Note (G2): ID from Kassis et al., 1997AJ....113.1723K 1997AJ....113.1723K,
<Cl* Berkeley 39 KVI NNNN> in Simbad.
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Acknowledgements:
Angela Bragaglia, angela.bragaglia(at)oabo.inaf.it
(End) Fabienne Woelfel, Patricia Vannier [CDS] 15-Feb-2013