J/A+A/565/A121 Abundances of 47 Tuc turn-off stars (Dobrovolskas+, 2014)
Abundances of lithium, oxygen, and sodium in the turn-off stars of
Galactic globular cluster 47 Tucanae.
Dobrovolskas V., Kucinskas A., Bonifacio P., Korotin S.A., Steffen M.,
Sbordone L., Caffau E., Ludwig H.-G., Royer F., Prakapavicius D.
<Astron. Astrophys., 565, A121-121 (2014)>
=2014A&A...565A.121D 2014A&A...565A.121D
ADC_Keywords: Clusters, globular ; Stars, dwarfs ; Abundances
Keywords: stars: abundances - stars: atmospheres -
globular clusters: individual: 47 Tucanae - techniques: spectroscopic
Abstract:
The cluster 47 Tuc is among the most metal-rich Galactic globular
clusters and its metallicity is similar to that of metal-poor disc
stars and open clusters. Like other globular clusters, it displays
variations in the abundances of elements lighter than Si, which is
generally interpreted as evidence of the presence of multiple stellar
populations.
We aim to determine abundances of Li, O, and Na in a sample of of 110
turn-off (TO) stars, in order to study the evolution of light elements
in this cluster and to put our results in perspective with
observations of other globular and open clusters, as well as with
field stars.
We use medium resolution spectra obtained with the GIRAFFE
spectrograph at the ESO 8.2m Kueyen VLT telescope and use state of the
art 1D model atmospheres and NLTE line transfer to determine the
abundances. We also employ CO5BOLD hydrodynamical simulations to
assess the impact of stellar granulation on the line formation and
inferred abundances.
Description:
Spectra of the TO stars in 47 Tuc investigated in this work were
obtained with the GIRAFFE spectrograph in August-September, 2008,
under the programme 081.D-0287(A) (PI: Shen). The same data set was
independently analysed by D'Orazi et al. (2010ApJ...713L...1D 2010ApJ...713L...1D, Cat.
J/ApJ/713/L1).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 75 110 List of the investigated TO stars in 47 Tuc,
their adopted atmospheric parameters and
determined abundances of Li, O, and Na
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See also:
J/ApJ/713/L1 : Lithium and proton-capture elements in 47 Tuc (D'Orazi+, 2010)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 8 I8 --- ID Identification number
10- 16 F7.5 deg RAdeg Right ascension (J2000)
18- 26 F9.5 deg DEdeg Declination (J2000)
28- 33 F6.3 mag Bmag [17.8/18.1] B magnitude
35- 40 F6.3 mag Vmag [17.2/17.6] V magnitude
42- 45 F4.2 [cm/s2] logg [3.98/4.14] Surface gravity
47- 50 I4 K Teff [5660/5968] Effective temperature
52- 55 F4.2 [-] A(Li)3N ?=- 3D NLTE lithium abundance (1)
57- 60 F4.2 [-] A(O)1N 1D NLTE oxygen abundance (1)
62- 65 F4.2 [-] A(O)3N 3D+NLTE oxygen abundance (1) (2)
67- 70 F4.2 [-] A(Na)1N ?=- 1D NLTE sodium abundance (1)
72- 75 F4.2 [-] A(Na)3N ?=- 3D+NLTE sodium abundance (1) (2)
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Note (1): The abundances were derived assuming identical microturbulence
velocity of ξmicro=1.0km/s for all stars; A(H)=12.
Note (2): 1D NLTE abundances with 3D-1D abundance corrections taken into
account.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 29-Jul-2014