J/A+A/656/A67 Abundance of Ba in 47 Tuc (Dobrovolskas+, 2021)
Abundance of barium in the atmospheres of red giants in the Galactic
globular cluster NGC 104 (47 Tuc).
Dobrovolskas V., Kolomiecas E., Kucinskas A., Klevas J., Korotin S.
<Astron. Astrophys. 656, A67 (2021)>
=2021A&A...656A..67D 2021A&A...656A..67D (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, globular ; Stars, late-type ; Abundances ; Optical
Keywords: techniques: spectroscopic - stars: abundances - stars: late-type -
globular clusters: individual: NGC 104
Abstract:
While most (if not all) Type I Galactic globular clusters (GGCs) are
characterised by spreads in the abundances of light chemical elements
(e.g. Li, N, O, Na, Mg, Al), it is not yet well established whether
similar spreads may exist in s-process elements as well.
We investigated the possible difference in Ba abundance between the
primordial (1P) and polluted (2P) stars in the Galactic globular
cluster (GGC) 47 Tuc (NGC 104). For this purpose, we obtained
homogeneous abundances of Fe, Na, and Ba in a sample of 261 red giant
branch (RGB) stars.
Abundances of Na and Ba were determined using archival GIRAFFE/VLT
spectra and 1D non-local thermodynamic equilibrium (NLTE) abundance
analysis methodology.
Contrary to the finding of Gratton et al. (2013A&A...549A..41G 2013A&A...549A..41G), we
did not detect any significant Ba-Na correlation or 2P-1P Ba
abundance difference in the sample of 261 RGB stars in 47 Tuc. This
corroborates the result of D'Orazi et al. (2010ApJ...719L.213D 2010ApJ...719L.213D),
who found no statistically significant Ba-Na correlation in 110 RGB
stars in this GGC. The average barium-to-iron ratio obtained in the
sample of 261 RGB stars, <[Ba/Fe]1DNLTE≥-0.01±0.06, agrees well
with those determined in Galactic field stars at this metallicity and
may therefore represent the abundance of primordial proto-cluster gas
that has not been altered during the subsequent chemical evolution of
the cluster.
Description:
Abundances of Fe, Na, and Ba determined in the sample of 261 stars in
47 Tuc. In cases when abundances were determined using data from
several observing programmes, microturbulence velocities and
abundances obtained using spectra from each individual program are
provided.
The IDs of individual stars and IDs of the corresponding observing
programmes are given in the last two columns, respectively:
072.D-0777(A), PI: P. Francois
073.D-0211(A), PI: E. Carretta
088.D-0026(A), PI: I. McDonald
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
tabled1.dat 99 310 Abundances of Fe, Na, and Ba
--------------------------------------------------------------------------------
See also:
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
Byte-by-byte Description of file: tabled1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 I19 --- GaiaEDR3 Gaia EDR3 identification number
22- 25 I4 K Teff Effective temperature
28- 31 F4.2 [cm/s2] logg Logarithm of the surface gravity
34- 37 F4.2 km/s vmic Microturbulence velocity
40- 43 F4.2 --- A(Fe) Iron abundance in the log(A(H))=12.0 scale
46- 50 F5.2 --- [Fe/H] Metallicity (1)
53- 56 F4.2 --- A(Na) Sodium abundance in the log(A(H))=12.0 scale
59- 62 F4.2 --- [Na/Fe] Sodium-over-iron abundance (2)
65- 68 F4.2 --- A(Ba) Barium abundance in the log(A(H))=12.0 scale
71- 75 F5.2 --- [Ba/Fe] Barium-over-iron abundance (3)
78- 84 A7 --- ID Star label in the observing programme
87- 99 A13 --- ObsProg ESO observing programme ID (4)
--------------------------------------------------------------------------------
Note (1): adopted solar iron abundance A(Fe) = 7.55
Note (2): adopted solar sodium abundance A(Na) = 6.17
Note (3): adopted solar barium abundance A(Ba) = 2.17
Note (4): Star label in the observing programme as follows:
072.D-0777(A) = PI: P. Francois
073.D-0211(A) = PI: E. Carretta
088.D-0026(A) = PI: I. McDonald
--------------------------------------------------------------------------------
Acknowledgements:
Vidas Dobrovolskas, vidas.dobrovolskas(at)tfai.vu.lt
(End) Patricia Vannier [CDS] 23-Sep-2021