J/ApJS/279/53 LAMOST VMP MSTO and red giant star metallicities (Li+, 2025)
A metallicity catalog of very metal-poor main-sequence turn-off and red giant
stars from LAMOST DR10.
Li X., Chen H., Huang Y., Zhang H., Beers T.C., Zhu L., Liu J.
<Astrophys. J. Suppl. Ser., 279, 53 (2025)>
=2025ApJS..279...53L 2025ApJS..279...53L
ADC_Keywords: Abundances, [Fe/H]; Equivalent widths; Stars, giant;
Stars, metal-deficient; Photometry; Proper motions;
Spectra, optical; Radial velocities
Keywords: Chemical abundances ; Galaxy stellar content ; Halo stars ;
Population II stars
Abstract:
We present a catalog of 8440 candidate very metal-poor (VMP;
[Fe/H]≤-2.0) main-sequence turn-off (MSTO) and red giant stars in the
Milky Way, identified from low-resolution spectra in LAMOST DR10. More
than 7000 of these candidates are brighter than G∼16, making them
excellent targets for high-resolution spectroscopic follow-up with
4-10m class telescopes. Unlike most previous studies, we employed an
empirical calibration to estimate metallicities from the equivalent
widths of the calcium triplet lines, taking advantage of the high
signal-to-noise ratio in the red arm of LAMOST spectra. We further
refined this calibration to improve its reliability for more distant
stars. This method enables robust identification of VMP candidates
with metallicities as low as [Fe/H]=-4.0 among both MSTO and red giant
stars. Comparisons with metal-poor samples from other spectroscopic
surveys and high-resolution follow-up observations confirm the
accuracy of our estimates, showing a typical median offset of ∼0.1dex
and a standard deviation of ∼0.2dex.
Description:
To ensure data quality, we selected low-resolution LAMOST DR10 spectra
with SNR greater than 20 in the r band. These were then crossmatched
with Gaia DR3 sources.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 302 8440 The metallicity catalog
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See also:
B/pastel : The PASTEL catalogue (Soubiran+, 2016-)
V/146 : LAMOST DR1 catalogs (Luo+, 2015)
II/358 : SkyMapper Southern Sky Survey. DR1.1 (Wolf+, 2018)
I/352 : Distances to 1.47 billion stars in Gaia EDR3 (Bailer-Jones+, 2021)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
I/357 : Gaia DR3 Part 3. Non-single stars (Gaia Collaboration, 2022)
V/162 : LAMOST DR11 catalogs (Luo+, 2026)
J/AJ/90/2089 : Stars of very low metal abundance. I (Beers+, 1985)
J/AJ/103/1987 : Stars of very low metal abundance (Beers+ 1992)
J/A+A/484/721 : HES survey. IV. Metal-poor stars (Christlieb+, 2008)
J/AJ/137/4377 : List of SEGUE plate pairs (Yanny+, 2009)
J/MNRAS/434/1681 : Extremely metal-poor stars CaII triplet (Carrera+, 2013)
J/MNRAS/478/4513 : GALAH Survey DR2 (Buder+, 2018)
J/ApJ/857/46 : Modelled vs observed abund. of EMP stars (Ishigaki+, 2018)
J/ApJS/238/16 : LAMOST-DR3 very metal-poor star catalog (Li+, 2018)
J/ApJS/245/34 : Abund. for 6 million stars from LAMOST DR5 (Xiang+, 2019)
J/A+A/649/A3 : Gaia EDR3 photometric passbands (Riello+, 2021)
J/ApJ/925/164 : Beyond spectrosc. I. Stars from SMSS & Gaia (Huang+, 2022)
J/ApJ/931/147 : Very metal-poor stars with LAMOST & Subaru. II. (Li+, 2022)
J/ApJS/259/60 : SEGUE-2 updated stellar parameter pipeline (Rockosi+, 2022)
J/ApJ/926/26 : Dynamically tagged groups of MP stars. I. (Shank+, 2022)
J/ApJ/943/23 : R-Process Alliance (RPA). II. Halo RPE stars (Shank+, 2023)
J/ApJ/947/23 : Chemodynamically groups of CEMP stars. I. (Zepeda+, 2023)
J/ApJS/273/12 : Metal-poor stars in the MW from SMSS & SAGES (Hong+, 2024)
J/A+A/683/L11 : Bright VPM stars from Gaia RVS spectra (Viswanathan+, 2024)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 I10 --- obsid [109238/1018110127] LAMOST DR10 unique
spectrum identifier
12- 30 I19 --- Gaia Gaia DR3 Source identifier
32- 41 F10.6 deg RAdeg Gaia DR3 right ascension in (ICRS) at
Epoch=2016
43- 51 F9.6 deg DEdeg [-8.8/86.2] Gaia DR3 declination in
(ICRS) at Epoch=2016
53- 58 F6.2 --- snr [10.4/999] Signal-to-noise ratio at
r-band of the LAMOST spectrum
60- 65 F6.3 mag Gmag [9.12/19.03] Gaia G passband magnitude
67- 71 F5.3 mag e_Gmag [0.003/0.02] Uncertainty in Gmag
73- 78 F6.3 mag Bpmag [9.59/19.5] Gaia Blue passband magnitude
80- 84 F5.3 mag e_Bpmag [0.003/0.06] Uncertainty in Bpmag
86- 91 F6.3 mag Rpmag [8.45/18.22] Gaia Red passband magnitude
93- 97 F5.3 mag e_Rpmag [0.004/0.04] Uncertainty in Rpmag
99- 102 I4 K TeffLASP [4022/6780]? Luo+ (2015, V/146) effective
temperature estimated
104- 106 I3 K e_TeffLASP [8/383]? Uncertainty in TeffLASP
108- 112 F5.3 [cm/s2] loggLASP [0.12/4.4]? Luo+ (2015, V/146) surface
gravity estimated
114- 118 F5.3 [cm/s2] e_loggLASP [0.01/0.6]? Uncertainty in loggLASP
120- 125 F6.3 [-] [Fe/H]LASP [-2.5/-1.5]? Luo+ (2015, V/146)
Metallicity estimated
127- 131 F5.3 [-] e_[Fe/H]LASP [0.004/0.32]? Uncertainty in [Fe/H]LASP
133- 139 F7.3 mas/yr pmTot [0.02/305.6] Gaia DR3 proper motion
141- 148 F8.3 mas/yr pmRA [-163/306] Gaia DR3 proper motion in RA
150- 154 F5.3 mas/yr e_pmRA [0.006/0.3] Uncertainty in pmRA
156- 163 F8.3 mas/yr pmDE [-274/67] Gaia DR3 proper motion in DE
165- 169 F5.3 mas/yr e_pmDE [0.006/0.3] Uncertainty in pmDE
171- 177 F7.2 km/s RVel [-592/487] Radial velocity offset from
the rest frame
179- 183 F5.2 km/s e_RVel [0/52] Uncertainty in RVel
185- 192 F8.2 pc Rgeo [157.9/33931] Bailer-Jones+ (2021, I/352)
geometric distance estimated
194- 201 F8.2 pc e_Rgeo [0.47/15543] Uncertainty in Rgeo
203- 206 F4.2 mag E(B-V) [0/2.3] Interstellar reddening
208- 212 F5.2 mag GmagC [8.57/18.9] De-reddened Gaia G passband
magnitude
214- 218 F5.2 mag BpmagC [8.7/19.3] De-reddened Gaia Blue passband
magnitude
220- 224 F5.2 mag RpmagC [8.2/18.1] De-reddened Gaia Red passband
magnitude
226- 230 F5.2 0.1nm EW1 [-0.06/4.74] First CaII (8500Å) triple
line equivalent width; Angstroms
232- 235 F4.2 0.1nm e_EW1 [0/0.3] Uncertainty in EW1
237- 242 F6.2 --- chi1 [0/591.3] First CaII (8500Å) triple
line χ2 of the spectra fitting
244- 247 F4.2 0.1nm EW2 [0.2/2.71] Second CaII (8544Å) triple
line equivalent width; Angstroms
249- 252 F4.2 0.1nm e_EW2 [0/0.2] Uncertainty in EW2
254- 259 F6.2 --- chi2 [0/235] Second CaII (8544Å) triple line
χ2 of the spectra fitting
261- 264 F4.2 0.1nm EW3 [0.3/2.2] Third CaII (8664Å) triple
line equivalent width; Angstroms
266- 269 F4.2 0.1nm e_EW3 [0/0.2] Uncertainty in EW3
271- 276 F6.2 --- chi3 [0/237] Third CaII (8664Å) triple line
χ2 of the spectra fitting
278- 281 F4.2 0.1nm ErrAvg [0/0.06] Average noise of the continuum
in the spectrum
283 I1 --- q_EW1 [0/1] Quality flag of EW1
285- 290 F6.3 [-] [Fe/H] [-3.4/-2] Spectroscopic metallicity
derived in this work using LAMOST
spectrum
292- 296 F5.3 [-] e_[Fe/H] [0.006/0.5] Uncertainty in [Fe/H]
298- 302 A5 --- n_[Fe/H] Method used in deriving [Fe/H] (1)
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Note (1): Method as follows:
color = Method 2: The Color and Surface Gravity Method (Section 3.2).
mag = Method 1: The Absolute Magnitude Method (Section 3.1).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 25-Feb-2026