J/ApJS/278/23 Barium abundances from LAMOST MRS DR9 spectra (Chen+, 2025)
Barium abundances from the LAMOST Medium-Resolution Survey stellar spectra.
Chen T.-Y., Shi J.-R., Yan H.-L., Beers T.C., Li C.-Q., Ding M.-Y.,
Xie X.-J., Shuai L., Zhou Z., Tang Y.-J.
<Astrophys. J. Suppl. Ser., 278, 23 (2025)>
=2025ApJS..278...23C 2025ApJS..278...23C
ADC_Keywords: Abundances; Spectra, red; Surveys
Keywords: Stellar abundances ; Sky surveys ; Catalogs
Abstract:
Based on a template-matching method, we estimate the barium (Ba)
abundances for stellar spectra from the Large Sky Area Multi-Object
Fiber Spectroscopic Telescope (LAMOST) Medium-Resolution Spectroscopic
Survey (MRS). The Ba abundances of 198,011 stars have been determined
from MRS spectra with signal-to-noise ratios (S/N)>40 combined with
the stellar atmospheric parameters from the LAMOST Low-Resolution
Spectroscopic Survey DR9 by the LAMOST Stellar Parameter Pipeline. The
uncertainties in the Ba abundances from the LAMOST MRS spectra are
less than 0.3 dex when S/N exceeds 40, which align closely with the
results based on the high-resolution UVES spectra from the Gaia-ESO
survey obtained by spectral synthesis. Further analysis of Ba
abundances from repeated observations of the same stars reveals that
random errors related to spectral quality remain below 0.3 dex at the
same S/N, with a systematic overestimation for the low-S/N spectra.
This extensive sample of stellar Ba abundances will enhance studies of
the s-, i-, and r-processes, and deepen our understanding of the
chemical-evolution history of the Milky Way.
Description:
The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST)
is a 4m reflective Schmidt Telescope with 4000 fibers covering a field
of view of 20deg2 on the sky.
Since 2018, LAMOST has been conducting the Medium-Resolution
Spectroscopic Survey (MRS) and has released more than 8,000,000 MR
spectra in DR9. As shown in Figure 1, each MRS spectrum consists of a
blue band (4950-5350Å) and a red one (6300-6800Å). In
particular, the red band covers a prominent BaII absorption line at
6496Å, which can be utilized to estimate the abundance of Ba.
We extract stellar parameters such as effective temperature (Teff),
surface gravity (logg), and metallicity ([Fe/H]) from the stellar
parameter catalog of the LAMOST LRS.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 149 198011 Barium abundances from LAMOST MRS DR9
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See also:
V/162 : LAMOST DR11 catalogs (Luo+, 2026)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
J/ApJ/617/1091 : La and Eu abundances in 85 stars (Simmerer+, 2004)
J/MNRAS/404/1529 : s-process in low-metallicity stars (Bisterzo+, 2010)
J/ApJ/787/10 : Solar s-process contrib. with GCE model (Bisterzo+, 2014)
J/MNRAS/448/822 : LAMOST candidate members of star clusters (Xiang+, 2015)
J/other/RAA/16.G10 : [alpha/Fe] ratios from LAMOST spectra (Li+, 2016)
J/AJ/151/144 : ASPCAP weights for APOGEE chemical elements (Garcia+, 2016)
J/ApJ/833/225 : -2.6≤[Fe/H]≤0.2 F & G dwarfs. II. Abundances (Zhao+, 2016)
J/A+A/606/A94 : Chemical abundances of 1059 FGK stars (Delgado Mena+, 2017)
J/ApJ/869/50 : Barium abundances of red giant branch stars (Duggan+, 2018)
J/ApJS/234/31 : Carbon stars from LAMOST using machine learning (Li+, 2018)
J/MNRAS/490/2219 : s-process enhanced stars in LAMOST (Norfolk+, 2019)
J/ApJS/245/34 : Abund. for 6 million stars from LAMOST DR5 (Xiang+, 2019)
J/MNRAS/506/150 : The GALAH+ Survey DR3 (Buder+, 2021)
J/ApJ/914/116 : Lithium abundances from LAMOST MRS. I. (Gao+, 2021)
J/ApJS/271/58 : Lithium abundances from LAMOST MRS DR9 spectra (Ding+, 2024)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- LAMOST LAMOST MRS DR9 Position-based Designation
21- 39 I19 --- GaiaDR3 ?=-9999 Gaia DR3 source identifier
41- 55 F15.11 deg RAdeg Right Ascension (J2000) (1)
57- 70 F14.11 deg DEdeg [-9.3/61.2] Declination (J2000) (1)
72- 75 I4 K Teff [3785/7999] Effective temperature
77- 80 F4.2 [cm/s2] logg [0.02/4.9] Log, Surface gravity
82- 86 F5.2 [-] FeH [-2.5/0.5] Metallicity, [Fe/H]
88- 90 I3 --- SN [40/632] Spectrum signal-to-noise per
pixel
92- 96 F5.2 [-] BaFe [-1/2.9] Relative barium abundance (to
iron), [Ba/Fe]
98- 105 F8.2 [-] delta [0/2.8]?=-9999 Maximum difference in
[Ba/Fe] derived from repeated
observations
107- 115 F9.3 [-] sigma [0/1.4]?=-9999 Standard deviation of
[Ba/Fe] derived from repeated
observations
117- 124 F8.2 [-] d-T+100 [-6.1/5.2]?=-9999 Change of [Ba/Fe]
caused by Teff+100K
126- 133 F8.2 [-] d-logg+0.25 [-4.92/4.63]?=-9999 Change of [Ba/Fe]
caused by logg+0.25
135- 142 F8.2 [-] d-feh+0.1 [-3.1/2.7]?=-9999 Change of [Ba/Fe]
caused by [Fe/H]+0.1
144- 149 F6.2 [-] d-xi+0.3 [-11.3/1.1] Change of [Ba/Fe] caused by
xi+0.3
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Note (1): Positions from Gaia DR3 if available, otherwise LAMOST MRS DR9.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 13-Feb-2026