J/ApJ/896/64 Barium abundances from Keck/HIRES high res. spectra (Liu+, 2020)
Keck/HIRES spectroscopic analysis of barium abundances.
Liu S., Shi J., Wu Z.
<Astrophys. J., 896, 64 (2020)>
=2020ApJ...896...64L 2020ApJ...896...64L
ADC_Keywords: Abundances; Stars, fundamental; Optical
Keywords: Stellar abundances ; Galaxy structure
Abstract:
Based on the high-resolution, high signal-to-noise-ratio spectra from
the Keck/HIRES, we have analyzed the barium abundances of 602 stars.
The parameter space of our sample are in the range of 4700<Teff<6100K,
-0.1<[Fe/H]<0.6dex, and 2<logg<5dex. It is found that the nonlocal
thermodynamic equilibrium (NLTE) effects are large for barium, and the
barium abundances can be underestimated by up to 0.2dex compared to
the the local thermodynamic equilibrium analysis for lines at 5853 and
6141Å. In addition, the average barium abundances of the high- and
low-α stars are -0.10 and 0.00dex, respectively, and higher
[Ba/Fe] corresponds to a lower [Mg/Fe] ratio. We note that there are
18 Ba-rich stars (with [Ba/Fe]>0.3 in NLTE), which contains six dwarfs
and 12 giants. The Ba-rich objects make up around 3% in our sample.
Description:
We have analyzed the barium abundances of a sample of 602 stars from
the Keck/HIRES spectrograph (R=60000). The wavelengths of the spectra
are divided into three sections of 3640 to 4790Å, 4970 to 6420Å,
and 6540 to 7980Å, which contain three BaII lines at 4554, 5853,
and 6141Å.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 83 602 Barium abundances of sample stars
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See also:
J/MNRAS/404/1529 : s-process in low-metallicity stars (Bisterzo+, 2010)
J/A+A/511/L10 : Abundances and space velocities of 94 stars (Nissen+, 2010)
J/A+A/530/A15 : Abundances of 94 stars (Nissen+, 2011)
J/A+A/545/A32 : Chemical abundances of 1111 FGK stars (Adibekyan+, 2012)
J/A+A/562/A71 : Abundances of solar neighbourhood dwarfs (Bensby+, 2014)
J/ApJ/787/10 : Solar s-process contributions (Bisterzo+, 2014)
J/ApJS/210/20 : Small Kepler planets radial velocities (Marcy+, 2014)
J/A+A/572/A108 : 47 Tuc red giants chemical composition (Thygesen+, 2014)
J/A+A/574/A50 : Chemical abundances of giants and subgiants (Jofre+, 2015)
J/ApJS/225/32 : Extended abundance analysis of cool stars (Brewer+, 2016)
J/A+A/606/A94 : Chemical abundances of 1059 FGK stars (Delgado Mena+, 2017)
J/MNRAS/476/5216 : Thick disc probability of GALAH stars (Duong+, 2018)
J/A+A/622/L4 : Carbon and oxygen in metal-poor halo stars (Amarsi+, 2019)
J/A+A/626/A128 : Main-sequence and subgiant Barium stars (Escorza+, 2019)
J/A+A/626/A127 : Barium and related stars and WD companions (Jorissen+, 2019)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Star name
12- 15 I4 K Teff [4702/6219] Stellar effective
temperature (1)
17- 20 F4.2 [cm/s2] logg [2.7/4.83] Stellar surface gravity (1)
22- 26 F5.2 --- [Fe/H] [-0.99/0.55] Metallicity (1)
28- 32 F5.2 --- [Mg/Fe] [-0.23/0.29] Magnesium-to-Iron
abundance ratio, log
34- 37 F4.2 km/s vt [0.85/0.85] Microturbulent velocity
39- 43 F5.2 --- [Ba/Fe]LTE1 [-0.35/0.72] Relative abundance,
5853Å line, assuming LTE
45- 49 F5.2 --- [Ba/Fe]NLTE1 [-0.4/0.6] Relative abundance,
5853Å line, assuming LTE
51- 55 F5.2 --- [Ba/Fe]LTE2 [-0.45/0.8] Relative abundance,
6141Å line, assuming LTE
57- 61 F5.2 --- [Ba/Fe]NLTE2 [-0.55/0.69] Relative abundance,
6141Å line, assuming LTE
63- 67 F5.2 --- [Ba/Fe]LTE [-0.34/0.76] Relative abundance,
combined, assuming LTE
69- 72 F4.2 --- e_[Ba/Fe]LTE [0/0.16] Uncertainty in [Ba/Fe]-LTE
74- 78 F5.2 --- [Ba/Fe]NLTE [-0.38/0.64] Relative abundance,
combined, assuming LTE
80- 83 F4.2 --- e_[Ba/Fe]NLTE [0/0.19] Uncertainty in [Ba/Fe]-NLTE
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Note (1): For all stars except GL 406 the measurement of Teff, logg, and [Fe/H]
comes from Brewer+, 2016, J/ApJS/225/32 ; note added by CDS.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 19-Oct-2021