A Comparison of Stellar Elemental Abundance Techniques and Measurements

Abstract

Stellar elemental abundances are important for understanding the fundamental properties of a star or stellar group, such as age and evolutionary history, as well as the composition of an orbiting planet. However, as abundance measurement techniques have progressed, there has been little standardization between individual methods and their comparisons. As a result, different stellar abundance procedures determine measurements that vary beyond quoted error for the same elements within the same stars (Hinkel et al. 2014). The purpose of this paper is to better understand the systematic variations between methods and offer recommendations for producing more accurate results in the future. We have invited a number of participants from around the world (Australia, Portugal, Sweden, Switzerland, and USA) to calculate ten element abundances (C, O, Na, Mg, Al, Si, Fe, Ni, Ba, and Eu) using the same stellar spectra for four stars (HD361, HD10700, HD121504, HD202206). Each group produced measurements for each of the stars using: 1) their own autonomous techniques, 2) standardized stellar parameters, 3) standardized line list, and 4) both standardized parameters and line list. We present the resulting stellar parameters, absolute abundances, and a metric of data similarity that quantifies homogeneity of the data. We conclude that standardization of some kind, particularly stellar parameters, improves the consistency between methods. However, because results did not converge as more free parameters were standardized, it is clear there are inherent issues within the techniques that need to be reconciled. Therefore, we encourage more conversation and transparency within the community such that stellar abundance determinations can be reproducible as well as accurate and precise.

arXiv comment86 pages, 5 figures, 24 tables, accepted to Astrophysical Journal Supplement

References in corpus (102)

• The chemical composition of the Sun
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• Exploring the Milky Way stellar disk. A detailed elemental abundance study of 714 F and G dwarf stars in the Solar neighbourhood
• Spectroscopic [Fe/H] for 98 extra-solar planet-host stars: Exploring the probability of planet formation
• Galactic Chemical Evolution: Hydrogen Through Zinc
• Solar Chemical Abundances Determined with a CO5BOLD 3D Model Atmosphere
• New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey
• Stellar Chemical Signatures And Hierarchical Galaxy Formation
• The Chemical Compositions of Galactic Disk F and G Dwarfs
• alpha-, r-, and s-process element trends in the Galactic thin and thick disks
• Chemical abundances of 1111 FGK stars from the HARPS GTO planet search program.Galactic stellar populations and planets
• Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 parsecs: The Southern Sample
• Near-Field Cosmology with Metal-Poor Stars
• Determining stellar atmospheric parameters and chemical abundances of FGK stars with iSpec
• The peculiar solar composition and its possible relation to planet formation
• ULySS: A Full Spectrum Fitting Package
• The Exoplanet Orbit Database
• Stellar Iron Abundances: non-LTE Effects
• Abundances for metal-poor stars with accurate parallaxes I. Basic data
• S4N: A Spectroscopic Survey of Stars in the Solar Neighborhood
• Improved spectroscopic parameters for transiting planet hosts
• A new code for automatic determination of equivalent widths: Automatic Routine for line Equivalent widths in stellar Spectra (ARES)
• Gaia FGK Benchmark Stars - Metallicity
• The Compositional Diversity of Extrasolar Terrestrial Planets: I. In-Situ Simulations
• Parent Stars of Extrasolar Planets VI: Abundance Analyses of 20 New Systems
• The Abundances of Neutron Capture Species in the Very Metal-Poor Globular Cluster M15: An Uniform Analysis of RGB and RHB Stars
• Gaia FGK Benchmark Stars: Effective temperatures and surface gravities
• Stellar Abundances in the Solar Neighborhood: The Hypatia Catalog
• High-precision abundances of elements in solar twin stars: Trends with stellar age and elemental condensation temperature
• The Stagger-grid: A Grid of 3D Stellar Atmosphere Models - I. Methods and General Properties
• Fundamental Properties of Stars using Asteroseismology from Kepler & CoRoT and Interferometry from the CHARA Array
• Oxygen Abundances in Nearby FGK Stars and the Galactic Chemical Evolution of the Local Disk and Halo
• The Exoplanet Orbit Database II: Updates to exoplanets.org
• Accurate fundamental parameters for 23 bright solar-type stars
• Gaia-ESO Survey: The analysis of high-resolution UVES spectra of FGK-type stars
• ARES v2 - new features and improved performance
• Accurate parameters of 93 solar-type Kepler targets
• Oxygen Abundances in Nearby Stars. Clues to the formation and evolution of the Galactic disk
• Prospecting in late-type dwarfs: a calibration of infrared and visible spectroscopic metallicities of late-K and M dwarfs spanning 1.5 dex
• Chemical Clues on the Formation of Planetary Systems: C/O vs Mg/Si for HARPS GTO Sample
• Chemical abundances of 451 stars from the HARPS GTO planet search program: Thin disc, thick disc, and planets
• Chemical abundances of the Milky Way thick disk and stellar halo II.: sodium, iron-peak and neutron-capture elements
• Gaia FGK benchmark stars: abundances of alpha and iron-peak elements
• Abundance trends in kinematical groups of the Milky Way's disk
• Abundances in metal-rich stars - Detailed abundance analysis of 47 G and K dwarf stars with [Me/H] $>$ 0.10 dex
• Automated derivation of stellar atmospheric parameters and chemical abundances: the MATISSE algorithm
• Abundances of refractory elements in the atmospheres of stars with extrasolar planets
• The Gaia FGK Benchmark Stars - High resolution spectral library
• Searching for the signatures of terrestial planets in solar analogs
• Carbon and oxygen abundances in stellar populations
• Atomic and Molecular Data for Optical Stellar Spectroscopy
• Non-LTE Line-Formation and Abundances of Sulfur and Zinc in F, G, and K Stars
• The origin and evolution of the odd-Z iron-peak elements Sc, V, Mn, and Co in the Milky Way stellar disk
• Constraining planet structure from stellar chemistry: the cases of CoRoT-7, Kepler-10, and Kepler-93
• Searching for the signatures of terrestrial planets in F-, G-type main-sequence stars
• The broadening of Fe II lines by neutral hydrogen collisions
• The Abundance Distribution in the Extrasolar-Planet Host Star HD19994
• On the Perils of Hyperfine Splitting: A reanalysis of Mn and Sc Abundance Trends
• Observable Signatures of Planet Accretion in Red Giant Stars I: Rapid Rotation and Light Element Replenishment
• New and updated stellar parameters for 90 transit hosts. The effect of the surface gravity
• C, S, Zn and Cu abundances in planet-harbouring stars
• Chemical Abundances of the Milky Way Thick Disk and Stellar Halo I.: Implications of [alpha/Fe] for Star Formation Histories in Their Progenitors
• Abundances of neutron-capture elements in stars of the galactic disk substructures
• Accurate spectroscopic parameters of WASP planet host stars
• Oxygen abundances in G- and F-type stars from HARPS
• Silicon and Oxygen Abundances in Planet-Host Stars
• Chemical abundances of planet-host stars: Results for alpha and Fe-group elements
• C/O Ratios of Stars with Transiting Hot Jupiter Exoplanets
• A Kine-Chemical Investigation of the AB Dor Moving Group "Stream"
• Systematic NLTE study of the -2.6 < [Fe/H] < 0.2 F and G dwarfs in the solar neighbourhood. I. Stellar atmosphere parameters
• M31 Globular Cluster Abundances from High-Resolution, Integrated-Light Spectroscopy
• Carbon and Oxygen in Nearby Stars: Keys to Protoplanetary Disk Chemistry
• The metallicity signature of evolved stars with planets
• Chemical Composition of Faint (I~21 mag) Microlensed Bulge Dwarf OGLE-2007-BLG-514S
• Elemental abundances of low-mass stars in nearby young associations: AB Doradus, Carina Near, and Ursa Major
• Chemical signatures of planets: beyond solar-twins
• Identifying the best iron-peak and $\alpha$-capture elements for chemical tagging: The impact of the number of lines on measured scatter
• Beyond the Iron Peak: r- and s-process Elemental Abundances in Stars with Planets
• Testing the chemical tagging technique with open clusters
• Beryllium and Alpha-Element Abundances in a Large Sample of Metal-Poor Stars
• Abundance ratios of volatile vs. refractory elements in planet-harbouring stars: hints of pollution?
• Parent Stars of Extrasolar Planets. VIII. Chemical Abundances for 18 Elements in 31 Stars
• Elemental Abundances of Solar Sibling Candidates
• Quantitative chemical tagging, stellar ages and the chemo-dynamical evolution of the Galactic disc
• The Penn State - Torun Centre for Astronomy Planet Search stars. II. Lithium abundance analysis of the Red Giant Clump sample
• Mn abundances in the stars of the Galactic disc with metallicities -1.0 < [Fe/H] < 0.3
• The Chemical Composition of τ Ceti and Possible Effects on Terrestrial Planets
• The NLTE Barium Abundance in Dwarf Stars in the Metallicity Range of -1 < [Fe/H] < +0.3
• Copper and Barium Abundances in the Ursa Major Moving Group
• Chemical abundances and kinematics of 257 G-, K-type field giants. Setting a base for further analysis of giant-planet properties orbiting evolved stars
• Chemical analysis of CH stars - I: atmospheric parameters and elemental abundances
• Non-LTE analysis of neutral copper in the late-type metal-poor stars
• Molybdenum, Ruthenium, and the Heavy r-process Elements in Moderately Metal-Poor Main-Sequence Turnoff Stars
• The photospheric solar oxygen project: II. Non-concordance of the oxygen abundance derived from two forbidden lines
• Some Aspects of the calculation of Balmer lines in the sun and stars
• A new procedure for defining a homogenous line-list for solar-type stars
• A Catalog of Stellar Evolution Profiles and the Effects of Variable Composition on Habitable Systems
• Stellar substructures in the solar neighbourhood. I. Kinematic group 3 in the Geneva-Copenhagen survey
• Palladium and silver abundances in stars with [Fe/H] > -2.6
• Stellar substructures in the solar neighbourhood. III. Kinematic group 2 in the Geneva-Copenhagen survey
• Stellar substructures in the solar neighbourhood. II. Abundances of neutron-capture elements in the kinematic Group 3 of the Geneva-Copenhagen survey
• Chemical composition of giants from two moving groups

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• Retired A Stars Revisited: An Updated Giant Planet Occurrence Rate as a Function of Stellar Metallicity and Mass
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• Gaia FGK Benchmark stars: Opening the black box of stellar element abundance determination
• $R$-process enhancements of Gaia-Enceladus in GALAH DR3
• Phylogeny of the Milky Way's inner disk and bulge populations: Implications for gas accretion, (the lack of) inside-out thick disk formation, and quenching
• Spectral Properties of Cool Stars: Extended Abundance Analysis of Kepler Objects of Interest
• Catalog for the ESPRESSO blind radial velocity exoplanet survey
• Characterisation of the hydrospheres of TRAPPIST-1 planets
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• A Catalog of Stellar Unified Properties (CATSUP) for 951 FGK-Stars Within 30 pc
• OCCASO II. Physical parameters and Fe abundances of Red Clump stars in 18 Open Clusters
• Plausible constraints on the range of bulk terrestrial exoplanet compositions in the Solar neighbourhood
• Uniform Forward-Modeling Analysis of Ultracool Dwarfs. II. Atmospheric Properties of 55 Late-T Dwarfs
• Disentangling Hot Jupiters formation location from their chemical composition
• Searching for Giant Exoplanets around M-dwarf Stars (GEMS) I: Survey Motivation
• Measuring Elemental Abundances of JWST Target Stars for Exoplanet Characterization I. FGK Stars
• Kepler-11 is a Solar Twin: Revising the Masses and Radii of Benchmark Planets Via Precise Stellar Characterization
• Atmospheric stellar parameters for large surveys using FASMA, a new spectral synthesis package
• HD 202206 : A Circumbinary Brown Dwarf System
• Catalog of Chromium, Cobalt, and Nickel Abundances in Globular Clusters and Dwarf Galaxies
• Small Planets in the Galactic Context: Host Star Kinematics, Iron, and $\alpha$ Element Enhancement
• The CARMENES search for exoplanets around M dwarfs: Not-so-fine hyperfine-split vanadium lines in cool star spectra
• Forming planets around stars with non-solar elemental composition
• Titans metal-poor reference stars. I. Accurate effective temperatures and surface gravities for dwarfs and subgiants from 3D non-LTE H$\alpha$ profiles and Gaia parallaxes
• A Recommendation Algorithm to Predict Giant Exoplanet Host Stars Using Stellar Elemental Abundances
• Systematic Differences in Spectroscopic Analysis of Red Giants
• A Concise Treatise on Converting Stellar Mass Fractions to Abundances to Molar Ratios
• Characterisation of 92 Southern TESS Candidate Planet Hosts and a New Photometric [Fe/H] Relation for Cool Dwarfs
• The consistency of chemical clocks among coeval stars
• The peculiar chemical pattern of the WASP-160 binary system: signatures of planetary formation and evolution?
• Planetary mass-radius relations across the galaxy
• NGC 6752 AGB Stars Revisited: I. Improved AGB temperatures remove apparent overionisation of Fe I
• The GALAH Survey: Using Galactic Archaeology to Refine our Knowledge of TESS Target Stars
• Climbing the cosmic ladder with stellar twins in RAVE with Gaia
• Sun-like stars unlike the Sun: Clues for chemical anomalies of cool stars
• Revisiting equilibrium condensation and rocky planet compositions: Introducing the ECCOplanets code
• A Differential Abundance Analysis of Very Metal-Poor Stars
• First direct measurement of the 64.5 keV resonance strength in ${}^{17}$O(p,$\gamma$)${}^{18}$F reaction
• The effect of hyperfine splitting on Stark broadening for three blue-green Cu I lines in laser-induced plasma
• Characterization of Exoplanet-Host Stars
• Validating Stellar Abundance Measurements from Multi-Resolution Spectroscopy
• Gemini-GRACES high-quality spectra of Kepler evolved stars with transiting planets I. Detailed characterization of multi-planet systems Kepler-278 and Kepler-391
• Towards characterising rocky worlds: Trends in chemical make-ups of M dwarfs versus GK dwarfs
• New Temperature and Metallicity Scale of Cool Giants from K-band Spectra
• The Fraction of Distilled White Dwarfs with Long-Lived Habitable Zones
• "In-System" Fission-Events: An Insight into Puzzles of Exoplanets and Stars?
• The SOL $\text{(Solar Origin and Life)}$ Project: Detailed characterization of candidates for the ZAMS and Subgiant stages
• Playing CHESS with stars. I. Search for similar stars in large spectroscopic data sets
• Metallicities in M dwarfs: Investigating different determination techniques