J/AJ/165/145 FeI and FeII abundances with LOTUS (Li+, 2023)
LOTUS; A (Non-)LTE Optimization Tool for Uniform Derivation of Stellar
Atmospheric Parameters.
Li Y., Ezzeddine R.
<Astron. J., 165, 145 (2023)>
=2023AJ....165..145L 2023AJ....165..145L (SIMBAD/NED BibCode)
ADC_Keywords: Models; Stars, atmospheres; Abundances, [Fe/H];
Effective temperatures; Spectra, optical
Keywords: Stellar physics; Stellar atmospheres; Astronomical techniques
Spectroscopy; Stellar abundances; Effective temperature
Surface gravity; Metallicity; Fundamental parameters of stars
Stellar photospheres
Abstract:
Precise fundamental atmospheric stellar parameters and abundance
determination of individual elements in stars are important for all
stellar population studies. Non-local thermodynamic equilibrium
(non-LTE; hereafter NLTE) models are often important for such high
precision, however, can be computationally complex and expensive,
which renders the models less utilized in spectroscopic analyses. To
alleviate the computational burden of such models, we developed a
robust 1D, NLTE fundamental atmospheric stellar parameter derivation
tool, LOTUS, to determine the effective temperature Teff, surface
gravity logg, metallicity [Fe/H], and microturbulent velocity vmic
for FGK-type stars, from equivalent width (EW) measurements of FeI and
FeII lines. We utilize a generalized curve of growth method to take
into account the EW dependencies of each FeI and FeII line on the
corresponding atmospheric stellar parameters. A global differential
evolution optimization algorithm is then used to derive the
fundamental parameters. Additionally, LOTUS can determine precise
uncertainties for each stellar parameter using a Markov Chain Monte
Carlo algorithm. We test and apply LOTUS on a sample of benchmark
stars, as well as stars with available asteroseismic surface gravities
from the K2 survey, and metal-poor stars from the Gaia-ESO and
R-Process Alliance surveys. We find very good agreement between our
NLTE-derived parameters in LOTUS to nonspectroscopic values on average
within Teff=±30K, and logg=±0.10dex for benchmark stars. We
provide open access of our code, as well as of the interpolated
precomputed NLTE EW grids available on Github (the software is
available on GitHubunder an MIT License, and version 0.1.1 (as the
persistent version) is archived in Zenodo) and documentation with
working examples.
Description:
We present the open-source code, local thermodynamic equilibrium (LTE)
optimization tool for uniform derivation of stellar atmospheric
parameters (LOTUS), developed to automatically derive fast and precise
atmospheric stellar parameters (Teff, logg, [Fe/H], and vmic) of
stars in 1D, LTE, and 1D, Non-LTE using FeI and FeII equivalent width
measurement from stellar spectra.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 24 459 FeI and FeII linelist selected for LOTUS
table3.dat 134 179 Derived stellar atmospheric parameters of the
target stars
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See also:
III/283 : RAVE 6th data release (Steinmetz+, 2020)
V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)
J/PASJ/57/109 : Late-G giants abundances (Takeda+, 2005)
J/A+A/512/A54 : Teff and Fbol from Infrared Flux Method (Casagrande+, 2010)
J/A+A/530/A138 : Geneva-Copenhagen survey re-analysis (Casagrande+, 2011)
J/A+A/558/A38 : FAMA code stellar parameters and abundances (Magrini+, 2013)
J/ApJ/769/57 : Equivalent widths of metal-poor stars (Frebel+, 2013)
J/A+A/564/A119 : CoRoT red giants abundances (Morel+, 2014)
J/A+A/564/A133 : Gaia FGK benchmark stars; metallicity (Jofre+, 2014)
J/A+A/575/A26 : Properties of Population II star HD 140283 (Creevey+, 2015)
J/MNRAS/450/397 : Spectroscopic study of RGs in Kepler field (Takeda+, 2015)
J/A+A/587/A2 : SP_Ace derived data from stellar spectra (Boeche+, 2016)
J/A+A/592/A70 : Gaia FGK stars; low-metallicities candidates (Hawkins+, 2016)
J/AJ/151/144 : ASPCAP weight for 15 APOGEE chemical elements (Garcia+, 2016)
J/A+A/608/A89 : Very metal poor stars in MW halo (Mashonkina+, 2017)
J/ApJ/847/142 : Ultrametalpoor stars LTE & NLTE abundances (Ezzeddine+, 2017)
J/A+A/612/A90 : Inelastic Fe+H collision data (Barklem, 2018)
J/AJ/156/18 : APOGEE DR14;Binary comp. evolved stars (Price-Whelan+, 2018)
J/ApJ/858/92 : RPA Southern Pilot Search of 107 Stars (Hansen+, 2018)
J/ApJ/865/129 : Abundance analysis of HD 222925 (Roederer+, 2018)
J/ApJ/868/110 : R-Process Alliance; DR1 in Galactic halo (Sakari+, 2018)
J/A+A/625/A33 : Radial velocity time series of HD 122563 (Creevey+, 2019)
J/A+A/628/A54 : Fe, Mg, Ti in Galactic clusters (Kovalev+, 2019)
J/A+A/640/A25 : Metal-poor stars limb-darkening coeff. (Karovicova+, 2020)
J/A+A/643/A83 : K2-Gaia-ESO stellar param. and abundances (Worley+, 2020)
J/ApJ/898/150 : High-res. MIKE obs. of metal-poor stars (Ezzeddine+, 2020)
J/ApJS/249/30 : R-Process Alliance; metal-poor star spectro (Holmbeck+, 2020)
J/A+A/645/A106 : Atomic data for the Gaia-ESO Survey (Heiter+, 2021)
J/A+A/650/A194 : Titans metal-poor reference stars. I. (Giribaldi+, 2021)
J/A+A/658/A47 : Dwarf stars limb-darkening coefficients (Karovicova+, 2022)
J/A+A/658/A48 : 7 giants/subgiants limb-darkening coeff (Karovicova, 2022)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 A4 --- Species Species
6- 12 F7.2 0.1nm Wave [3440/8221] Wavelength, Angstroms
14- 17 F4.2 eV ExPot [0/5.1] Excitation potential
19- 24 F6.3 [-] loggf [-5.97/0.65] log, statistical weight*oscillator
strength
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 1 I1 --- Subset [1/5] Subset (1)
3- 19 A17 --- Name Star Name (2)
21- 24 I4 K Teff-LTE [4270/6493] LTE Surface Effective
Temperature, LTE
26- 28 I3 K e_Teff-LTE [15/289] Uncertainty in Teff-LTE
30- 33 F4.2 [cm/s2] logg-LTE [0.06/4.55] log, surface gravity, cgs, LTE
35- 38 F4.2 [cm/s2] e_logg-LTE [0.03/1] Uncertainty in logg-LTE
40- 44 F5.2 [-] FeH-LTE [-3.17/0.42] Metallicity, LTE
46- 49 F4.2 [-] e_FeH-LTE [0.01/0.3] Uncertainty in FeH-LTE
51- 54 F4.2 km/s vt-LTE [0.59/2.81] microturbulent velocity, LTE
56- 59 F4.2 km/s e_vt-LTE [0.01/0.7] Uncertainty in vt-LTE
61- 63 A3 --- NFeI-LTE Number, FeI lines, LTE
65- 66 A2 --- NFeII-LTE Number, FeII lines, LTE
68- 70 F3.1 --- Chi-LTE [0/2.7] Cutoff, χ^2, LTE
72- 75 I4 K Teff-NLTE [4234/6407] Surface Effective Temperature,
NLTE
77- 79 I3 K e_Teff-NLTE [15/251] Uncertainty in Teff-LTE
81- 84 F4.2 [cm/s2] logg-NLTE [0.11/4.66] log, surface gravity, cgs, NLTE
86- 89 F4.2 [cm/s2] e_logg-NLTE [0.04/0.8] Uncertainty in logg-LTE
91- 95 F5.2 [-] FeH-NLTE [-3.01/0.45] Metallicity, NLTE
97-100 F4.2 [-] e_FeH-NLTE [0.01/0.3] Uncertainty in FeH-LTE
102-105 F4.2 km/s vt-NLTE [0.63/2.8] microturbulent velocity, NLTE
107-110 F4.2 km/s e_vt-NLTE [0.01/0.4] Uncertainty in vt-LTE
112-114 A3 --- NFeI-NLTE Number, FeI lines, NLTE
116-117 A2 --- NFeII-NLTE Number, FeII lines, NLTE
119-121 F3.1 --- Chi-NLTE [0/2.7] Cutoff, χ2, NLTE
123-128 F6.2 --- SNR [19/850] Signal-to-Noise
130-134 A5 --- Ref References (3)
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Note (1): Subset as follows:
1 = Widely analyzed stars
2 = GES Metal-Poor Stars, Hawkins+, 2016, J/A+A/592/A70
3 = CHARA Interferometry Stars, Karovicova+, 2020, J/A+A/640/A25, &
2022, J/A+A/658/A47 and 2022, J/A+A/658/A48
4 = R-Process Alliance Stars, Hansen+, 2018, J/ApJ/858/92
5 = GES-K2 Stars, Worley+, 2020, J/A+A/643/A83
Note (2): For HD121370, parameters are obtained with the average of
runs inputting 3 different EW line lists: EPINARBO and BOLOGNA in
Heiter+, 2015A&A...582A..49H 2015A&A...582A..49H, and Takeda+, 2005ARA&A..43..481A 2005ARA&A..43..481A. In
LTE, there are NFeI=79,121,46, NFeII=6,9,4 lines in these three line
list respectively; In NLTE,NFeI=79,121,47, NFeII=6,9,4
Note (3): References as follows:
F2013 = Frebel+, 2013, J/ApJ/769/57
H2015 = Heiter+, 2015A&A...582A..49H 2015A&A...582A..49H
H2016 = Hawkins+, 2016A&A...592A..70H 2016A&A...592A..70H
H2018 = Hansen+, 2018, J/ApJ/858/92
L2020 = Liu+, 2020, J/MNRAS/495/3961
M2014 = Morel+, 2014, J/A+A/564/A119
T2005 = Takeda+, 2005ARA&A..43..481A 2005ARA&A..43..481A
T2015 = Takeda & Tajitsu, 2015, J/MNRAS/450/397
W2020 = Worley+, 2020, J/A+A/643/A83
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 19-Jul-2023