J/ApJ/931/147 Very metal-poor stars with LAMOST & Subaru. II. (Li+, 2022)
Four-hundred very metal-poor stars studied with LAMOST and Subaru.
II. Elemental abundances.
Li H., Aoki W., Matsuno T., Xing Q., Suda T., Tominaga N., Chen Y.,
Honda S., Ishigaki M.N., Shi J., Zhao J., Zhao G.
<Astrophys. J., 931, 147 (2022)>
=2022ApJ...931..147L 2022ApJ...931..147L
ADC_Keywords: Stars, metal-deficient; Spectra, optical; Abundances
Keywords: Population II stars ; Chemical abundances ; Galaxy chemical evolution
Abstract:
We present homogeneous abundance analysis of over 20 elements for
385 very metal-poor (VMP) stars based on the LAMOST survey and
follow-up observations with the Subaru Telescope. It is the largest
high-resolution VMP sample (including 363 new objects) studied by a
single program, and the first attempt to accurately determine
evolutionary stages for such a large sample based on Gaia parallaxes.
The sample covers a wide metallicity range from [Fe/H]≲-1.7 down to
[Fe/H]~-4.3, including over 110 objects with [Fe/H]≲-3.0. The
expanded coverage in evolutionary status makes it possible to define
the abundance trends respectively for giants and turnoff stars. The
newly obtained abundance data confirm most abundance trends found by
previous studies, but also provide useful updates and new samples of
outliers. The Li plateau is seen in main-sequence turnoff stars with
-2.5<[Fe/H]<-1.7 in our sample, whereas the average Li abundance is
clearly lower at lower metallicity. Mg, Si, and Ca are overabundant
with respect to Fe, showing decreasing trend with increasing
metallicity. Comparisons with chemical evolution models indicate that
the overabundance of Ti, Sc, and Co are not well reproduced by current
theoretical predictions. Correlations are seen between Sc and
α-elements, while Zn shows a detectable correlation only with Ti
but not with other α-elements. The fraction of carbon-enhanced
stars ([C/Fe]>0.7) is in the range of 20%-30% for turnoff stars
depending on the treatment of objects for which C abundance is not
determined, which is much higher than that in giants (∼8%). Twelve
Mg-poor stars ([Mg/Fe]<0.0) have been identified in a wide metallicity
range from [Fe/H]~-3.8 through -1.7. Twelve Eu-rich stars
([Eu/Fe]>1.0) have been discovered in -3.4<[Fe/H]<-2.0, enlarging
the sample of r-process-enhanced stars with relatively high
metallicity.
Description:
Readers can find more details about the sample and observations in
Paper I (Aoki+ 2022, J/ApJ/931/146). The original sample includes
420 objects (with 445 Subaru/HDS spectra; R=36000). In order to obtain
sufficient spectral quality to derive the reliable parameters and
elemental abundances, spectra with S/N higher than 10 per pixel around
4500Å, or those in which more than 10 FeI lines are detected, have
been selected for the following analysis.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 116 385 Stellar parameters of the program stars
table3.dat 70 8470 Abundances and abundance error estimations of
the program stars
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See also:
B/subaru : Log of Subaru Prime Focus Camera Exposures (ADAC NAOJ, 2007)
V/164 : LAMOST DR5 catalogs (Luo+, 2019)
I/350 : Gaia EDR3 (Gaia Collaboration, 2020)
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+AS/117/227 : Dwarf effective temperatures (Alonso+ 1996)
J/A+A/354/169 : Metal-poor field stars abundances (Gratton+, 2000)
J/A+A/416/1117 : Abundances in the early Galaxy (Cayrel+, 2004)
J/ApJ/617/1091 : La and Eu abundances in 85 stars (Simmerer+, 2004)
J/A+A/439/129 : HERES II. Spectroscopic analysis (Barklem+, 2005)
J/A+A/442/961 : Lithium content of the Gal. Halo stars (Charbonnel+, 2005)
J/ApJ/655/492 : Equivalent widths of 26 metal-poor stars (Aoki+, 2007)
J/ApJ/667/1267 : CrI transition probabilities (Sobeck+, 2007)
J/A+A/484/721 : HES survey. IV. Cand. metal-poor stars (Christlieb+, 2008)
J/ApJ/681/1524 : Detailed abundances for 28 metal-poor stars (Lai+, 2008)
J/A+A/501/519 : Extremely metal-poor turnoff stars abund. (Bonifacio+, 2009)
J/A+A/503/545 : Equivalent widths of Li, Na, Fe, Ca in NGC6397 (Lind+, 2009)
J/AJ/137/4377 : List of SEGUE plate pairs (Yanny+, 2009)
J/ApJ/724/341 : Nucleosynthesis of massive metal-free stars (Heger+, 2010)
J/MNRAS/403/1413 : Updated stellar yields from AGB models (Karakas, 2010)
J/A+A/516/A46 : HE 2327-5642 abundance analysis (Mashonkina+, 2010)
J/A+A/511/L10 : Abundances and space velocities of 94 stars (Nissen+, 2010)
J/A+A/522/A26 : Fe Abundances in metal-poor stars (Sbordone+ 2010)
J/ApJ/742/54 : CASH project II. Extremely metal-poor stars (Hollek+, 2011)
J/AJ/141/175 : Abundances in M15 RGB/RHB stars (Sobeck+, 2011)
J/MNRAS/412/843 : SAGA extremely metal-poor stars (Suda+, 2011)
J/ApJS/199/38 : Presupernova evolution (Limongi+, 2012)
J/ApJ/751/102 : Equivalent widths of 9 RGB in Carina dSph (Venn+, 2012)
J/AJ/145/13 : Metal-poor stars from SDSS/SEGUE. I. Abund. (Aoki+, 2013)
J/ApJ/778/56 : Hamburg/ESO Survey extremely metal-poor stars (Cohen+, 2013)
J/ApJ/769/57 : Equivalent widths of metal-poor stars (Frebel+, 2013)
J/ApJ/762/25 : The most metal-poor stars in HES & SDSS. I. (Norris+, 2013)
J/ApJ/762/26 : Most metal-poor stars. II. Galactic halo stars (Yong+, 2013)
J/ApJ/797/44 : Evolution and nucleosynthesis of AGB stars (Fishlock+, 2014)
J/ApJ/781/40 : Metal-poor stars from HES survey. II. Sp. (Placco+, 2014)
J/ApJ/797/21 : Carbon-enhanced metal-poor stars (Placco+, 2014)
J/AJ/147/136 : Stars of very low metal abundance. VI. (Roederer+, 2014)
J/ApJ/807/171 : SkyMapper Survey metal-poor star sp. (Jacobson+, 2015)
J/ApJ/798/110 : Equivalent widths of LAMOST metal-poor stars (Li+, 2015)
J/A+A/586/A120 : Grid of 1D models for Mg line formation (Osorio+, 2016)
J/AJ/151/82 : The 4 brightest red giants in Ret 2 (Roederer+, 2016)
J/ApJ/833/20 : Carbon-enhanced metal-poor (CEMP) star abund. (Yoon+, 2016)
J/AJ/154/52 : Metal-poor stars from SDSS/SEGUE. I. (Matsuno+, 2017)
J/A+A/608/A46 : Constraining cosmic scatter (Reggiani+, 2017)
J/A+A/618/A133 : Non standard s-process in massive stars (Choplin+, 2018)
J/ApJ/855/63 : Yields of Fe & Zn for different types of SNe (Hirai+, 2018)
J/ApJS/238/16 : LAMOST-DR3 very metal-poor star catalog (Li+, 2018)
J/ApJS/237/13 : Models & yields of 13-120M☉ stars (Limongi+, 2018)
J/A+A/618/A134 : Omega Cen lower red giant stars abund. (Mucciarelli+, 2018)
J/ApJ/857/2 : Abundances in 6 metal-poor stars (Roederer+, 2018)
J/ApJ/865/129 : Abundance analysis of HD 222925 (Roederer+, 2018)
J/ApJ/868/110 : R-Process Alliance: 1st release in Gal. halo (Sakari+, 2018)
J/ApJ/857/111 : Stellar yields of rot. first stars. II. (Takahashi+, 2018)
J/ApJ/883/84 : MIKE obs. of 2 metal-poor stars (Roederer+, 2019)
J/ApJ/874/148 : Metal-poor star RAVE J093730.5-062655 abund. (Sakari+, 2019)
J/ApJ/872/137 : Abund. of red clump & RGBs with APOGEE (Shetrone+, 2019)
J/ApJ/898/150 : High-res. MIKE obs. of metal-poor stars (Ezzeddine+, 2020)
J/ApJ/897/183 : Abundances of 3 stars in Grus II galaxy (Hansen+, 2020)
J/ApJS/249/30 : R-Process Alliance: metal-poor star sp. (Holmbeck+, 2020)
J/ApJ/903/88 : Ions individual abund. in LAMOST J1109+0754 (Mardini+, 2020)
J/MNRAS/497/L7 : Gal. disc Pristine low-metallicity stars (Sestito+, 2020)
J/MNRAS/492/3241 : The Pristine survey. IX. (Venn+, 2020)
J/ApJ/891/39 : LAMOST very metal-poor stars of the Gal. halo (Yuan+, 2020)
J/MNRAS/500/889 : S2 stream. Shreds of a primitive dwarf gal. (Aguado+, 2021)
J/ApJ/931/146 : Very metal-poor stars with LAMOST & Subaru. I. (Aoki+, 2022)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- ID Short ID of a star, Paper I
(Aoki+ 2022, J/ApJ/931/146)
13- 22 F10.6 deg RAdeg Right Ascension in degrees (J2000)
24- 32 F9.6 deg DEdeg [-7.1/60.6] Declination in degrees (J2000)
34- 39 F6.1 km/s RVel [-454/434] Radial velocity (observed)
41- 45 F5.1 --- SNR [6.9/157] Spectral SNR around 4500 Angstrom
47- 50 I4 K Teff [4290/6731] Effective temperature derived
from Subaru spectra
52- 54 I3 K e_Teff [7/584] Uncertainty on Teff
56- 59 F4.2 [cm/s2] logg [0.5/4.8] Surface gravity derived from Subaru
spectra
61- 64 F4.2 [cm/s2] e_logg [0.01/0.7] Uncertainty on logg
66- 70 F5.2 [-] FeH [-4.4/-0.6] Metallicity derived from Subaru
spectra
72- 75 F4.2 [-] e_FeH [0.08/0.4] Uncertainty on FeH
77- 80 F4.2 km/s vt [0/4.1] Microturbulent velocity derived from
Subaru spectra
82- 85 F4.2 km/s e_vt [0.03/0.3] Uncertainty on Vt
87- 92 F6.3 [Lsun] logLum [-0.5/3.4] Luminosity derived from the Subaru
spectra
94- 98 F5.3 [Lsun] e_logLum [0.017/0.7] Uncertainty on logLum
100 I1 --- f_logg [0/1]? Flag on logg (1)
102- 105 I4 K Teff-L [4376/6597] Effective temperature derived
from LAMOST spectra
107- 110 F4.2 [cm/s2] logg-L [0.8/5.2] Surface gravity derived from LAMOST
spectra
112- 116 F5.2 [-] FeH-L [-4.2/-1.3] Metallicity derived from LAMOST
spectra
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Note (1): Flag as follows:
0 = logg have been estimated based on reliable parallaxes;
1 = logg based on empirical correction from the spectroscopic estimation.
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 10 A10 --- ID Short ID of a star, Paper I
(Aoki+ 2022, J/ApJ/931/146)
13- 16 A4 --- Ion Species of atom
18 A1 --- l_logeps Limit flag for logeps
20- 24 F5.2 [-] logeps [-2.9/8.42]? Log number abundance of Ion
26 A1 --- l_XFe Limit flag for XFe
28- 32 F5.2 [-] XFe [-2.2/4.6]? Abundance ratio of [X/Fe]
34- 38 F5.2 --- sigTeff [-0.31/0.5]? Abundance error associated
with Teff uncertainty
40- 44 F5.2 --- siglogg [-0.26/0.26]? Abundance error associated
with logg uncertainty
46- 50 F5.2 --- sigFeH [-0.15/0.11]? Abundance error associated
with [Fe/H] uncertainty
52- 56 F5.2 --- sigvt [-0.22/0.14]? Abundance error associated
with microturbulent velocity uncertainty
58- 61 F4.2 --- sigN [0/0.8]? Abundance error associated with
measurement uncertainty
63- 66 F4.2 --- sigTot [0.01/0.8]? Total abundance error
68- 70 I3 --- Nl [0/163] Number of adopted lines
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History:
From electronic version of the journal
References:
Aoki et al. Paper I. 2022ApJ...931..146A 2022ApJ...931..146A Cat. J/ApJ/931/146
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 09-Apr-2024