ASPCAP: The Apogee Stellar Parameter and Chemical Abundances Pipeline

Abstract

The Apache Point Observatory Galactic Evolution Experiment (APOGEE) has built the largest moderately high-resolution (R=22, 500) spectroscopic map of the stars across the Milky Way, and including dust-obscured areas. The APOGEE Stellar Parameter and Chemical Abundances Pipeline (ASPCAP) is the software developed for the automated analysis of these spectra. ASPCAP determines atmospheric parameters and chemical abundances from observed spectra by comparing observed spectra to libraries of theoretical spectra, using chi-2 minimization in a multidimensional parameter space. The package consists of a fortran90 code that does the actual minimization, and a wrapper IDL code for book-keeping and data handling. This paper explains in detail the ASPCAP components and functionality, and presents results from a number of tests designed to check its performance. ASPCAP provides stellar effective temperatures, surface gravities, and metallicities precise to 2%, 0.1 dex, and 0.05 dex, respectively, for most APOGEE stars, which are predominantly giants. It also provides abundances for up to 15 chemical elements with various levels of precision, typically under 0.1 dex. The final data release (DR12) of the Sloan Digital Sky Survey III contains an APOGEE database of more than 150,000 stars. ASPCAP development continues in the SDSS-IV APOGEE-2 survey.

19 pages,11 figures - Submitted to The Astronomical Journal

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• M giants with IGRINS I. Stellar parameters and $\alpha$-abundance trends of the solar neighborhood population
• Probing the early Milky Way with GHOST spectra of an extremely metal-poor star in the Galactic disk
• Spinning up the Surface: Evidence for Planetary Engulfment or Unexpected Angular Momentum Transport?
• NLTE Analysis of High Resolution H-band Spectra. II. Neutral Magnesium
• An enquiry on the origins of N-rich stars in the inner Galaxy basedon APOGEE chemical compositions
• Massive stars in the SDSS-IV/APOGEE SURVEY. I- OB stars
• Mapping the distribution of OB stars and associations in Auriga
• An Empirical Template Library for FGK and Late--type A Stars Using LAMOST Observed Spectra
• Actions are weak stellar age indicators in the Milky Way disk
• APOGEE-2S view of the globular cluster Patchick 125 (Gran 3). New metallicity and elemental abundances from high-resolution spectroscopy
• The Galactic Interstellar Object Population: A Framework for Prediction and Inference
• Gaia-ESO Survey: INTRIGOSS - A new library of High Resolution Synthetic Spectra
• Galactic Chemical Evolution Models Favor an Extended Type Ia Supernova Delay-Time Distribution
• Characterizing Observed Extra Mixing Trends in Red Giants using the Reduced Density Ratio from Thermohaline Models
• The chemical properties of the Milky Way's on-bar and off-bar regions: evidence for inhomogeneous star formation history in the bulge
• Elemental Abundances in M31: Iron and Alpha Element Abundances in M31's Outer Halo
• SDSS-IV MaStar: Data-driven Parameter Derivation for the MaStar Stellar Library
• The Rotation of M Dwarfs Observed by the Apache Point Galactic Evolution Experiment
• White dwarf binaries Across the H-R Diagram
• Characterization of Kepler targets based on medium-resolution LAMOST spectra analyzed with ROTFIT
• Stellar Properties for a Comprehensive Collection of Star Forming Regions in the SDSS APOGEE-2 Survey
• An Investigation of Non-Canonical Mixing in Red Giant Stars Using APOGEE 12C/13C Ratios Observed in Open Cluster Stars
• TOI-150: A transiting hot Jupiter in the TESS southern CVZ
• Updated extraction of the APOGEE 1.5273 μm diffuse interstellar band: a Planck view on the carrier depletion in dense cores
• Galactic ArchaeoLogIcaL ExcavatiOns (GALILEO) II. t-SNE Portrait of Local Fossil Relics and Structures
• Searching for Solar Siblings in APOGEE and $Gaia$ DR2 with N-body Simulations
• APOGEE/Kepler Overlap Yields Orbital Solutions for a Variety of Eclipsing Binaries
• Inference of stellar parameters from brightness variations
• Rotation of Kepler field dwarfs and sub giants: Spectroscopic $v\sin I$ from APOGEE
• Data-Driven Stellar Models
• Stellar parameters for the First Release of the MaStar Library: An Empirical Approach
• Time evolution of Ce as traced by APOGEE using giant stars observed with the Kepler, TESS and K2 missions
• Assessing the physical reality of Milky Way open cluster candidates
• The metallicity effect on line-depth ratios in APOGEE $H$-band spectra
• High Velocity Stars in SDSS/APOGEE DR17
• Testing the chemical homogeneity of chemically tagged dissolved birth clusters
• Searching for a kinematic signature of the moderately metal-poor stars in the Milky Way bulge using N-body simulations
• Magnetic Fields of M Dwarfs from the Pleiades Open Cluster
• Evolution of the radial ISM metallicity gradient in the Milky Way disk since redshift $\approx 3$
• Geometry of the Draco C1 Symbiotic Binary
• The APOGEE Library of Infrared SSP Templates (A-LIST): High-Resolution Simple Stellar Population Spectral Models in the H-Band
• APOGEE-2 Discovery of a Large Population of Relatively High-Metallicity Globular Cluster Debris
• J-PLUS: Support Vector Regression to Measure Stellar Parameters
• The Origin of the 300 km s${}^{-1}$ Stream Near Segue 1
• Radial velocities in the outermost disk toward the anticenter
• Machine Learning Regression of extinction in the second $Gaia$ Data Release
• Elemental abundances distributions in (R, $V_{\varphi }$) plane with LAMOST DR5 and Gaia DR2
• Estimating Atmospheric Parameters from LAMOST Low-Resolution Spectra with Low SNR
• Chemical Cartography with APOGEE: Two-process Parameters and Residual Abundances for 288,789 Stars from Data Release 17
• Photometric Classifications of Evolved Massive Stars: Preparing for the Era of Webb and Roman with Machine Learning
• An extremely hot white dwarf with a rapidly rotating K-type subgiant companion: UCAC2 46706450
• An unsupervised method for identifying $X$-enriched stars directly from spectra: Li in LAMOST
• On the Hunt for the Origins of the Orphan--Chenab Stream: Detailed Element Abundances with APOGEE and Gaia
• A Model RRNet for Spectral Information Exploitation and LAMOST Medium-resolution Spectrum Parameter Estimation
• The chemical enrichment of the Milky Way disk evaluated using conditional abundances
• Homogeneous Stellar Atmospheric Parameters and 22 Elemental Abundances for FGK Stars Derived From LAMOST Low-resolution Spectra with DD-Payne
• LAMA: LAMOST Medium-Resolution Spectral Analysis Pipeline
• 44 New & Known M Dwarf Multiples In The SDSS-III/APOGEE M Dwarf Ancillary Science Sample
• Evidence of Deep Mixing in IRS 7, a Cool Massive Supergiant Member of the Galactic Nuclear Star Cluster
• APOGEE Detection of N-rich stars in the tidal tails of Palomar 5
• Line-depth ratios as indicators of effective temperature and surface gravity
• The Swan: Data-Driven Inference of Stellar Surface Gravities for Cool Stars from Photometric Light Curves
• Infrared Telescope Facility (IRTF) spectral library II: New indices in Y, J, H, and L atmospheric windows
• Red giants evolutionary status determination: the complete Kepler catalog
• Derivation of parameters for 3748 FGK stars using H-band spectra from APOGEE Data Release 14
• Unveiling the chemical fingerprint of phosphorus-rich stars I. In the infrared region of APOGEE-2
• Signatures of the Galactic bar on stellar kinematics unveiled by APOGEE
• Lithium in Kepler Red Giants: Defining Normal and Anomalous
• 3D Parameter Maps of Red Clump Stars in the Milky Way -- Absolute Magnitudes and Intrinsic Colors
• The Chemical Abundance Structure of the Inner Milky Way: A Signature of "Upside-Down" Disk Formation?
• The 15273 Å diffuse interstellar band in the dark cloud Barnard 68
• Is Terzan 5 the remnant of a building block of the Galactic bulge? Evidence from APOGEE
• Cool and Data-Driven: An Exploration of Optical Cool Dwarf Chemistry with Both Data-Driven and Physical Models
• Evidence of a large scale positive rotation-metallicity correlation in the Galactic thick disk
• The effect of surface gravity on line-depth ratios in the wavelength range 0.97-1.32 μm
• Where are the extremely metal-poor stars in the Milky Way and Andromeda? Expectations from TNG50
• An Ultraviolet-Optical Color-Metallicity relation for Red Clump Stars using GALEX and Gaia
• The Peculiar Globular Cluster Palomar 1 and Persistence in the SDSS-APOGEE Database
• APOGEE view of the globular cluster NGC 6544
• Mapping the Milky Way with Gaia Bp/Rp spectra I: Systematic flux corrections and atmospheric parameters for 68 million stars
• Chemical abundances and ages of the bulge stars in APOGEE high-velocity peaks
• SpectroTranslator: a deep-neural network algorithm to homogenize spectroscopic parameters
• A chemical and kinematical analysis of the intermediate-age open cluster IC 166 from APOGEE and Gaia DR2
• Carbon-enhanced metal-poor stars in the SDSS-APOGEE database
• Refractory and Volatile Species in the UV-to-IR Transmission Spectrum of Ultra-hot Jupiter WASP-178b with HST and JWST
• The SDSS-HET Survey of Kepler Eclipsing Binaries. Description of the Survey and First Results
• The Open Cluster Chemical Abundances and Mapping Survey: V. Chemical Abundances of CTIO/Hydra Clusters using The Cannon
• Existence of the Metal-Rich Stellar Halo and High-velocity Thick Disk in the Galaxy
• Chemodynamic evolution of Sun-like stars in nearby moving groups
• CAPOS: The bulge Cluster APOgee Survey V. Elemental abundances of the bulge globular cluster HP 1
• On the radial metallicity gradient and radial migration effect of the Galactic disk
• Chemical abundances of the young inner-disk open cluster NGC 6705 observed by APOGEE: sodium-rich and not $\alpha$-enhanced
• The Chemodynamics of the Stellar Populations in M31 from APOGEE Integrated Light Spectroscopy
• Probing the strength of radial migration via churning by using metal-rich red giant stars from APOGEE
• Estimation of stellar atmospheric parameters from LAMOST DR8 low-resolution spectra with 20$\le$SNR$<$30
• Spectroscopic analysis of the bulge Globular Cluster ESO~456-SC38
• StarFlow: Leveraging Normalizing Flows for Stellar Age Estimation in SDSS-V DR19
• Bar-spiral interaction produces radial migration and star formation bursts
• Acoustic modes in M67 cluster stars trace deepening convective envelopes
• A catalogue of asteroseismically calibrated ages for APOGEE DR17. The predictions of a CatBoost machine learning model based on the [Mg/Ce] chemical clock and other stellar parameters
• Measuring Dwarf Galaxy Intrinsic Abundance Scatter with Mid-resolution Spectroscopic Surveys: Calibrating APOGEE Abundance Errors
• Parameter Estimation of LAMOST Medium-resolution Stellar Spectra
• Are Milky-Way-like galaxies like the Milky Way? A view from SDSS-IV/MaNGA
• SDSS-IV MaStar: Stellar Parameter Determination with Continuum-Supplemented Full-Spectrum Fitting
• LOTUS: A (non-)LTE Optimization Tool for Uniform derivation of Stellar atmospheric parameters
• CAPOS: The bulge Cluster APOGEE Survey VI. Characterizing multiple stellar populations and chemical abundances in the bulge globular cluster NGC 6569
• Spectroscopic Observations of Obscured Populations in the Inner Galaxy: 2MASS-GC02, Terzan 4, and the 200 km/s stellar peak
• A Galactic Self-Portrait: Density Structure and Integrated Properties of the Milky Way Disk
• Mapping the Distant and Metal-Poor Milky Way with SDSS-V
• Chemo-Dynamical Tagging in the Outskirts: The Origins of Stellar Substructures in the Magellanic Clouds
• Towards a fully consistent Milky Way disk model V. The disk model for 4 $-$ 14 kpc
• Searching For Transiting Planets Around Halo Stars. I. Sample Selection and Validation
• Calibrating and standardizing the Tip of the Red Giant Branch in the Small Magellanic Cloud using small-amplitude red giants
• APOGEE-2S Mg-Al anti-correlation of the Metal-Poor Globular Cluster NGC 2298
• Kinematical Analysis of Substructure in the Southern Periphery of the Large Magellanic Cloud
• Spectroscopic confirmation of the binary nature of the hybrid pulsator KIC 5709664 found with the frequency modulation method
• The GALAH survey: Multiple stars and our Galaxy. I. A comprehensive method for deriving properties of FGK binary stars
• Investigating Phosphorus Abundances in a Sample of APOGEE-2 Bulge Globular Clusters
• The G 305 Star-forming Region: II. Irregular variable stars
• The Seventeenth Data Release of the Sloan Digital Sky Surveys: Complete Release of MaNGA, MaStar and APOGEE-2 Data
• Symbiotic Stars in the APOGEE Survey: The Case of LIN 358 and SMC N73 (LIN 445a)
• The Astrophysical Variance in Gaia-RVS Spectra
• Stellar Migration and Chemical Enrichment in the Milky Way Disc: A Hybrid Model
• Automated Pipelines for Spectroscopic Analysis
• Chemodynamically Characterizing the Jhelum Stellar Stream with APOGEE-2
• Reconstructing the Milky Way chemical map with Galactic Chemical Evolution tool OMEGA+ from SDSS-MWM
• Assessing the Accuracy of TESS Asteroseismology with APOGEE
• A baseline on the relation between chemical patterns and birth stellar cluster
• CoSHA: Code for Stellar properties Heuristic Assignment -- for the MaStar stellar library
• Fundamental properties of stars from Kepler and Gaia data: parallax offset and revised scaling relations
• CAPOS: The bulge Cluster APOgee Survey VII. First detailed chemical analysis of NGC 6316
• A Data-Driven Technique for Measuring Stellar Rotation
• Disentangling stellar atmospheric parameters in astronomical spectra using Generative Adversarial Neural Networks
• Pre-main Sequence Brackett Emitters in the APOGEE DR17 Catalog: Line Strengths and Physical Properties of Accretion Columns
• Yields from massive stars in binaries. Chemical evolution of the Milky Way disk
• CAPOS: The bulge Cluster APOgee Survey VIII. Final ASPCAP results for all clusters
• Analysis of Previously Classified White Dwarf-Main Sequence Binaries Using Data from the APOGEE Survey
• Prospects of measuring a metallicity trend and spread in globular clusters from low-resolution spectroscopy
• New Fe I Level Energies and Line Identifications from Stellar Spectra. III. Initial Results from UV, Optical, and Infrared Spectra
• Chemical tagging with APOGEE, MUSE, and HST: constraints on the formation of $\omega$ Centauri
• Asteroseismically Inferred Ages of 132,000 Red Giants with TESS
• Open cluster members in APOGEE DR17 I. Dynamics and star members
• Beyond the Nyquist frequency: Asteroseismic catalog of undersampled Kepler late subgiants and early red giants
• Characterization of low-mass companions to $\text{Kepler}$ objects of interest observed with APOGEE-N
• Elemental Abundances of Kepler Objects of Interest in APOGEE DR17
• Multiplicity Statistics of Stars in the Sagittarius Dwarf Spheroidal Galaxy: Comparison to the Milky Way
• Globular cluster candidates in the Sagittarius dwarf galaxy
• The DR14 APOGEE-TGAS catalogue: Precise chemo-kinematics in the extended solar vicinity
• tonalli: an asexual genetic code to characterise APOGEE-2 stellar spectra. I. Validation with synthetic and solar spectra
• Milky Way Mapper decoded abundances -- I. Shared disc enrichment patterns
• A Hint of Three-section Halo as Seen from the APOGEE DR14
• Disentanglement of the chemodynamical assembly: mapping the Milky Way disks
• The first low-mass eclipsing binary within the fully convective zone from TMTS
• Concerning Li-rich status of KIC~9821622: A Kepler field RGB star reported as Li-rich Giant
• Double-lined spectroscopic binaries in the APOGEE DR16 and DR17 data
• Towards Understanding the Milky Way's Typicality: Assessing the Chemodynamics of M31's Bulge & Bar, Thick & Thin Discs
• New families in our Solar neighborhood: applying Gaussian Mixture models for objective classification of structures in the Milky Way and in simulations
• Interpreting Stellar Spectra with Unsupervised Domain Adaptation
• Estimating Stellar Atmospheric Parameters and [α/Fe] for LAMOST O-M type Stars Using a Spectral Emulator
• The chemical and spatial variations of the bulge's velocity ellipsoids
• Scalable Stellar Parameter Inference Using Python-based LASP: From CPU Optimization to GPU Acceleration
• Not all nitrogen-rich field stars originate from globular clusters
• The metal-poor tail of the APOGEE survey I. Uncovering [Fe/H] < -2.5 stars from the inner Galaxy to the Magellanic Clouds
• The large-scale kinematics of young stars in the Milky Way disc: first results from SDSS-V
• On the connection between nitrogen-enhanced field stars and the Galactic globular clusters
• Refined M-type Star Catalog from LAMOST DR10: Measurements of Radial Velocities, $T_{\text{eff}}$, log $g$, [M/H] and [$\alpha$/M]
• Estimating stellar atmospheric parameters and elemental abundances using fully connected residual network
• PISP: Projected-Space Inference of Stellar Parameters
• Stellar multiplicity and stellar rotation: Insights from APOGEE
• Functional Data Analysis for Extracting the Intrinsic Dimensionality of Spectra: Application to Chemical Homogeneity in the Open Cluster M67
• Playing CHESS with stars. I. Search for similar stars in large spectroscopic data sets
• SDSS-IV MaStar: Theoretical Atmospheric Parameters for the MaNGA Stellar Library
• Validation of the Gaia Early Data Release 3 parallax zero-point model with asteroseismology
• SDSS-IV MaStar: Determination of Stellar Parameters Using Bayesian Averaging
• Chemical compositions of semi-regular variable red giants
• Gaia FGK Benchmark Stars: Selecting Infrared Lines for Abundance Determination
• Two sequences in the age-metallicity relation as seen from [C/N] abundances in APOGEE
• Tracing the assembly of the Milky Way's disk through abundance clustering