J/AJ/170/259 Barium stars 12C, 13C, N, and O abundances (Roriz+, 2025)
Exploring giant Barium stars:12C/13C ratio and elemental abundances of
Carbon, Nitrogen, and Oxygen.
Roriz M.P., Drake N.A., Holanda N., Lugaro M., Cseh B., Junqueira S.,
Pereira C.B.
<Astron. J., 170, 259 (2025)>
=2025AJ....170..259R 2025AJ....170..259R
ADC_Keywords: Abundances, peculiar; Abundances, [Fe/H]; Effective temperatures;
Molecular data; Spectra, optical; Stars, barium
Keywords: Stellar abundances ; Chemically peculiar giant stars ;
Stellar nucleosynthesis ; Asymptotic giant branch stars
Abstract:
Barium (Ba) stars belong to binary systems that underwent
mass-transfer events. As a consequence, their envelopes were enriched
with material synthesized in the interiors of their evolved companions
via slow neutron-capture nucleosynthesis, the s-process. As
postinteracting binaries, Ba stars figure as powerful tracers of the
s-process. In this study, we conduct a classical local thermodynamic
equilibrium analysis for a sample of 180 Ba giant stars to find
complementary insights for the s-process, in form of elemental
abundances of carbon, nitrogen, and oxygen, as well as the 12C/13C
ratio. We found carbon abundances systematically larger than those
observed in normal giants, with [C/Fe] ratios ranging within from
-0.30 to +0.60dex. As expected, the [C/Fe] ratios increase for lower
metallicity regimes and are strongly correlated with the average
s-process abundances. Nitrogen abundances have a flat behavior around
[N/Fe]~+0.50dex and are moderately correlated with sodium abundances.
Except for HD 107541, the entire sample shows C/O<1. We found
12C/13C<20 for ∼80% of the sampled stars and 12C/13C>60 for
three objects.
Description:
The stars analyzed here are the same objects sampled in the previous
works in this series (Castro+2016, J/MNRAS/459/4299;
Roriz+2021MNRAS.501.5834R; Roriz+2021MNRAS.507.1956R;
Roriz+2024MNRAS.528.4354R), which include the metal-rich Ba stars
analyzed by Pereira+2011 (J/A+A/533/A51). Their spectra were obtained
as a result of a spectroscopic survey conducted between 1999 and 2010,
in search of new chemically peculiar stars. The instrument used to
extract the stellar spectra was the Fiber-fed Extended Range Optical
Spectrograph (FEROS), attached to the 1.52 and 2.2m ESO telescopes at
La Silla, Chile. FEROS covers a spectral interval between 3500 and
9200Å, providing high-resolution spectroscopic data with a
resolving power R=λ/Δλ∼48,000.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 84 181 Carbon, Nitrogen, and Oxygen abundances, isotopic
ratios and other quantities
table4.dat 40 412 Line list near the spectral region of the C2 and CN
molecular absorption features
--------------------------------------------------------------------------------
See also:
J/A+A/356/238 : Atmospheric param. in metal-poor stars. III. (Carretta+ 2000)
J/A+A/354/169 : Metal-poor field stars abundances (Gratton+, 2000)
J/MNRAS/340/304 : [X/Fe] of Galactic disc F and G dwarfs (Reddy+, 2003)
J/A+A/402/343 : IR OI triplet, [OI] lines in F-K dwarfs/giants (Takeda, 2003)
J/A+A/417/269 : Equivalent widths of two post-AGB stars (Reyniers+, 2004)
J/ApJ/617/1091 : La and Eu abundances in 85 stars (Simmerer+, 2004)
J/A+A/454/895 : Abundances of 26 barium stars. I. (Allen+, 2006)
J/A+A/454/917 : Abundances of 26 barium stars. II. (Allen+, 2006)
J/MNRAS/367/1329 : Elemental abundances for 176 stars (Reddy+, 2006)
J/AJ/133/2464 : Parameters and abundances of nearby giants (Luck+, 2007)
J/ApJ/696/797 : Evolution and yields of low-mass AGB stars (Cristallo+, 2009)
J/A+A/509/A93 : Carbon-enhanced metal-poor stars (Masseron+, 2010)
J/A+A/533/A51 : Abundances of 12 metal-rich barium stars (Pereira+, 2011)
J/ApJ/764/78 : Oxygen abundances in nearby FGK stars (Ramirez+, 2013)
J/A+A/554/A106 : Abundance study of LMC post-AGB stars (van Aarle+, 2013)
J/A+A/583/A56 : Abundance study of two LMC post-AGB stars (De Smedt+, 2015)
J/MNRAS/459/4299 : Barium stars abundances and kinematics (de Castro+, 2016)
J/A+A/587/A6 : Linelist of 14 Galactic post-AGB stars (De Smedt+, 2016)
J/A+A/626/A127 : Barium and related stars and WD companions (Jorissen+, 2019)
J/MNRAS/486/3266 : Chemical analysis of CH stars (Purandardas+, 2019)
J/A+A/645/A61 : Abundances of 25 metal-poor stars (Karinkuzhi+, 2021)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 A12 --- Star Star
14- 17 I4 K Teff [4100/5400] Surface effective temperature
19- 22 F4.2 [cm/s] logg [1.1/3.3] Log of surface gravity
24- 28 F5.2 [Sun] [Fe/H] [-1.11/0.32] Metallicity
30- 33 F4.2 [Sun] [C] [7.32/8.82] C abundance, logε
(logAC)
35- 38 F4.2 [Sun] [N] [6.81/8.81] N abundance, logε
(logAN)
40- 43 F4.2 [Sun] [O] [8.03/9.05] O abundance, logε
(logAO)
45- 48 F4.2 [Sun] [C+N] [7.54/9.03] C+N abundance, logε
(logACpN)
50- 53 F4.2 --- C/N [0.19/4.79] C/N abundance ratio
55- 58 F4.2 --- C/O [0.16/1.32] C/O abundance ratio
60- 64 F5.2 [Sun] [C/Fe] [-0.29/0.6] [C/Fe] Abundance ratio
66- 70 F5.2 [Sun] [N/Fe] [-0.0/1.44] [N/Fe] Abundance ratio
72- 76 F5.2 [Sun] [O/Fe] [-0.1/0.31] [O/Fe] Abundance ratio
78- 79 A2 --- l_12C/13C Limit flag on 12C/13C
81- 82 I2 --- 12C/13C [6/80] Carbon isotopic ratio
84 A1 --- f_12C/13C :=uncertain quality of carbon ratio
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- Region Region (1)
4- 9 A6 --- Mol Molecule, atom, or ion (Molecule)
11- 19 F9.4 0.1nm lambda [5628/8008.1] Wavelength
21- 26 F6.4 [-] loggf [0/6.3] Log, statistical weight*oscillator
strength
28- 34 F7.4 eV ExPot [-8.35/0.22] Excitation potential
36- 40 F5.3 eV DE [6.24/7.73]? Dissociation energy
--------------------------------------------------------------------------------
Note (1): Region list as follows:
C2 = C2 region at 5628-5638Å (278 occurrences)
CN = CN region at 7997-8008Å (134 occurrences)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
License: CC-BY-4.0
(End) Prepared by [AAS], Robin Leichtnam [CDS] 24-Jul-2026