J/ApJS/274/39 DR5 of the R-Process Alliance: GTC sp. (Bandyopadhyay+, 2024)
The R-Process Alliance: fifth Data Release from the search for
r-process-enhanced metal-poor stars in the Galactic halo with the GTC.
Bandyopadhyay A., Ezzeddine R., Allende Prieto C., Aria N., Shah S.P.,
Beers T.C., Frebel A., Hansen T.T., Holmbeck E.M., Placco V.M.,
Roederer I.U., Sakari C.M.
<Astrophys. J. Suppl. Ser., 274, 39 (2024)>
=2024ApJS..274...39B 2024ApJS..274...39B
ADC_Keywords: Spectra, optical; Stars, metal-deficient; Radial velocities;
Infrared sources; Equivalent widths; Abundances; Stars, halo
Keywords: Stellar abundances ; R-process ; Nucleosynthesis ;
Population II stars ; Milky Way stellar halo ;
High resolution spectroscopy ; CEMP stars ; Nuclear astrophysics
Abstract:
Understanding the abundance pattern of metal-poor stars and the
production of heavy elements through various nucleosynthesis processes
offers crucial insights into the chemical evolution of the Milky Way,
revealing primary sites and major sources of rapid neutron-capture
process (r-process) material in the Universe. In this fifth data
release from the R-Process Alliance (RPA), we present the detailed
chemical abundances of 41 faint (down to V=15.8) and extremely
metal-poor (down to [Fe/H]=-3.3) halo stars selected from the RPA. We
obtained high-resolution spectra for these objects with the HORuS
spectrograph on the Gran Telescopio Canarias. We measure the
abundances of light, α, Fe-peak, and neutron-capture elements.
We report the discovery of five carbon-enhanced metal-poor, one
limited-r, three r-I, and four r-II stars, and six Mg-poor stars. We
also identify one star of a possible globular cluster origin at an
extremely low metallicity at [Fe/H]=-3.0. This adds to the growing
evidence of a lower-limit metallicity floor for globular cluster
abundances. We use the abundances of Fe-peak elements and the
α-elements to investigate the contributions from different
nucleosynthesis channels in the progenitor supernovae. We find the
distribution of [Mg/Eu] as a function of [Fe/H] to have different
enrichment levels, indicating different possible pathways and sites of
their production. We also reveal differences in the trends of the
neutron-capture element abundances of Sr, Ba, and Eu of various r-I
and r-II stars from the RPA data releases, which provide constraints
on their nucleosynthesis sites and subsequent evolution.
Description:
The observing program was carried out as a part of the R-Process
Alliance (RPA) "snapshot" survey efforts, during which moderately
high-resolution (R∼30000) spectra at intermediate signal-to-noise
ratios (SNR; ∼30) are obtained in order to identify new
r-process-enhanced (RPE) stars.
The targets were observed at a spectral resolving power of R∼25000,
using the High Optical Resolution Spectrograph (HORuS) on the 10.4m
Gran Telescopio Canarias (GTC) located on La Palma, Canary Islands,
Spain. Spectra for 45 metal-poor stars were obtained as a part of the
FILLER program on the GTC in 2020. Data for four objects had to be
discarded due to poor quality, reducing the number of stars in this
study to 41. The exposure times varied between 600s and 2000s.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 85 41 Observational details of the target stars
table2.dat 76 41 Stellar atmospheric parameters of the target stars
table5.dat 69 5524 Atomic line properties, equivalent widths,
absolute abundances, and measurement uncertainties
of the target stars
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See also:
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
V/156 : LAMOST DR7 catalogs (Luo+, 2019)
III/283 : RAVE 6th data release (Steinmetz+, 2020)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
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/ApJ/595/1154 : Oxygen abundances in metal-poor stars (Fulbright+, 2003)
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/AJ/130/2140 : Abundances & velocities in globular clusters (Pritzl+, 2005)
J/ApJ/655/492 : Equivalent widths of 26 metal-poor stars (Aoki+, 2007)
J/ApJ/681/1524 : Detailed abundances for 28 metal-poor stars (Lai+, 2008)
J/A+A/490/777 : Abundances of Population II stars in NGC 6397 (Lind+, 2008)
J/A+A/501/519 : Extremely metal-poor turnoff stars abund. (Bonifacio+, 2009)
J/A+A/505/139 : Abundances of red giants in 17 GCs (Carretta+, 2009)
J/ApJ/724/341 : Nucleosynthesis of massive metal-free stars (Heger+, 2010)
J/AJ/141/175 : Abundances in M15 RGB/RHB stars (Sobeck+, 2011)
J/ApJS/199/38 : Presupernova evolution (Limongi+, 2012)
J/ApJ/757/164 : Oxygen abundances of dwarf stars (Ramirez+, 2012)
J/ApJ/769/87 : Kinematics of halo red giants (Carollo+, 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/762/26 : Most metal-poor stars. II. 190 Gal. halo stars (Yong+, 2013)
J/ApJ/788/180 : Very metal-poor stars in the MW's halo (Carollo+, 2014)
J/ApJ/797/21 : Carbon-enhanced metal-poor stars (Placco+, 2014)
J/ApJ/797/69 : Abundances of late-type stars (Roederer+, 2014)
J/AJ/147/136 : Stars of very low metal abundance. VI. (Roederer+, 2014)
J/A+A/579/A28 : Abundances of 3 CEMP stars (Bonifacio+, 2015)
J/ApJ/830/93 : Abundances of Ret II brightest red giant members (Ji+, 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/ApJ/847/142 : Ultra-metal-poor stars LTE & NLTE abund. (Ezzeddine+, 2017)
J/MNRAS/465/501 : APOGEE N-rich stars in inner Galaxy (Schiavon+, 2017)
J/ApJ/864/43 : Abund. of 3 bright extremely metal-poor giants (Cain+, 2018)
J/ApJ/869/50 : Barium abundances of red giant branch stars (Duggan+, 2018)
J/ApJ/858/92 : RPA Southern Pilot Search of 107 Stars (Hansen+, 2018)
J/AJ/155/256 : Sp. validation of RAVE metal-poor stars (Placco+, 2018)
J/AJ/156/179 : r-process-enhanced field stars kinematics (Roederer+, 2018)
J/ApJ/868/110 : R-Process Alliance: 1st release in Gal. halo (Sakari+, 2018)
J/A+A/630/A104 : Disk and halo stars C, O and Fe abundances (Amarsi+, 2019)
J/A+A/631/A80 : Mn lines formation in late-type stars (Bergemann+, 2019)
J/MNRAS/490/2219 : s-process enhanced stars in LAMOST (Norfolk+, 2019)
J/ApJ/870/122 : Sp. of low-metallicity star candidates (Placco+, 2019)
J/ApJ/883/84 : MIKE obs. of 2 metal-poor stars in Sylgr (Roederer+, 2019)
J/ApJ/890/119 : Iron abund. in 3 very metal-poor stars (Cowan+, 2020)
J/ApJ/898/150 : High-res. MIKE obs. of metal-poor stars (Ezzeddine+, 2020)
J/ApJS/249/30 : RPA: metal-poor star spectroscopy (Holmbeck+, 2020)
J/ApJ/897/78 : RAVE J183013.5-455510 equivalent-widths (Placco+, 2020)
J/A+A/654/A170 : Abundances of metal-poor stars (Matas Pinto+, 2021)
J/other/Nat/601.45 : C-19 stream members (Martin+, 2022)
J/ApJS/260/27 : R-Process Alliance: UV sp. of HD 222925 (Roederer+, 2022)
J/A+A/671/A124 : Composition of 206 SMC red giants (Mucciarelli+, 2023)
J/A+A/682/A116 : Galactic halo stars abundances (Nissen+, 2024)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- --- [2MASS]
7- 23 A17 --- 2MASS 2MASS identifier (JHHMMSSss+DDMMSSs)
25 A1 --- f_2MASS Flag on 2MASS (1)
27- 28 I2 h RAh Hour of right ascension (J2000)
30- 31 I2 min RAm Minute of right ascension (J2000)
33- 38 F6.3 s RAs Second of right ascension (J2000)
40 A1 --- DE- Sign of declination (J2000)
41- 42 I2 deg DEd Degree of declination (J2000)
44- 45 I2 arcmin DEm Arcminute of declination (J2000)
47- 51 F5.2 arcsec DEs Arcsecond of declination (J2000)
53- 57 F5.2 mag Vmag [10.7/15.81]? Visual magnitude
59- 63 F5.2 mag Jmag [10.4/13.74] J-band magnitude
65- 68 I4 s Exp [600/2000] Exposure time
70- 71 I2 --- SNR [9/48] Signal-to-noise ratio at 5000Å
73- 78 F6.1 km/s RVGaia [-285.9/353.4]? Radial velocity from Gaia
80- 85 F6.1 km/s HRV [-392.2/353.4] Heliocentric radial velocity
from our spectra
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Note (1): Flag as follows:
a = Likely binary star, based on the reported RUWE from Gaia.
b = Potential binary star, based on deviations in RV of more than 1σ
between the Gaia RVs and our determination.
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- --- [2MASS]
7- 23 A17 --- 2MASS 2MASS identifier (JHHMMSSss+DDMMSSs)
25- 28 I4 K Teff [4140/5900] LTE effective temperature
30- 33 F4.2 [cm/s2] logg [0.02/3.92] LTE log of surface gravity
35- 38 F4.2 km/s Vt [0.49/3.46] LTE microturbulent velocity
40- 44 F5.2 [-] [Fe/H] [-3.45/-0.19] LTE metallicity
46- 49 I4 K Teffc [4396/5980] LTEcorr effective
temperature (2)
51- 54 F4.2 [cm/s2] loggc [0.58/4.13] LTEcorr log of surface gravity
56- 59 F4.2 km/s Vtc [0.92/3.81] LTEcorr microturbulent velocity
61- 65 F5.2 [-] [Fe/H]c [-3.3/-0.14] LTEcorr metallicity
67- 70 F4.2 [-] sigma [0.11/0.29] σ[FeI/H]
72- 73 I2 --- NFeI [32/92] Number of FeI lines
75- 76 I2 --- NFeII [3/14] Number of FeII lines
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Note (2): The corrected Teff were determined following the empirical calibration
of the derived Teff to a photometric scale as given by
Frebel+ 2013ApJ...769...57F 2013ApJ...769...57F: Teff(FR13corr)=0.9xTeff(LTE)+670
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Byte-by-byte Description of file: table5.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 5 A5 --- --- [2MASS]
7- 23 A17 --- 2MASS 2MASS identifier (JHHMMSSss+DDMMSSs)
25- 28 F4.1 --- Species [11.0/30.0] Species code identifier (1)
30- 37 F8.3 10-10m Wave [3842/6768] Wavelength; Angstroms
39- 43 F5.3 eV ExPot [0/4.6] Excitation potential
45- 50 F6.3 [-] loggf [-4.8/0.64] log oscillator strength
52- 57 F6.2 10-13m EW [1.5/447] Equivalent width; milli-Angstroms
59- 62 F4.2 10-13m e_EW [0.1/2] Uncertainty in EW
64- 69 F6.3 [-] A(X) [-0.52/7.74] log absolute abundance
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Note (1): In the code, XX.Y, XX is the atomic number and Y is the ionization,
e.g. 11.0 is Na I, 21.1 is Sc II, etc.
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History:
From electronic version of the journal
References:
Hansen et al. DR1-S. 2018ApJ...858...92H 2018ApJ...858...92H Cat. J/ApJ/858/92
Sakari et al. DR1-N. 2018ApJ...868..110S 2018ApJ...868..110S Cat. J/ApJ/868/110
Ezzeddine et al. MIKE 2020ApJ...898..150E 2020ApJ...898..150E Cat. J/ApJ/898/150
Holmbeck et al. DR4 2020ApJS..249...30H 2020ApJS..249...30H Cat. J/ApJS/249/30
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 11-Mar-2025