Beyond spectroscopy. I. Metallicities, distances, and age estimates for over twenty million stars from SMSS DR2 and Gaia EDR3

Abstract

Accurate determinations of stellar parameters and distances for large complete samples of stars are keys for conducting detailed studies of the formation and evolution of our Galaxy. Here we present stellar atmospheric parameters ($T_{\mathrm{eff}}$, luminosity classifications, and [Fe/H]) estimates for some 24 million stars determined from the stellar colors of SMSS DR2 and Gaia EDR3, based on training datasets with available spectroscopic measurements from previous high/medium/low-resolution spectroscopic surveys. The number of stars with photometric-metallicity estimates is 4-5 times larger than that collected by the current largest spectroscopic survey to date - LAMOST - over the course of the past decade. External checks indicate that the precision of the photometric-metallicity estimates are quite high, comparable to or slightly better than that derived from spectroscopy, with typical values around 0.05-0.15dex for both dwarf and giant stars with [Fe/H]>$-$1.0, 0.10-0.20dex for giant stars with $-$2.0<[Fe/H]<$-$1.0. and 0.20-0.25dex for giant stars with [Fe/H]<$-$2.0, and include estimates for stars as metal-poor as [Fe/H]~$-$3.5, substantially lower than previous photometric techniques. Photometric-metallicity estimates are obtained for an unprecedented number of metal-poor stars, including a total of over three million metal-poor (MP; [Fe/H] <$-$1.0) stars, over half a million very metal-poor (VMP; [Fe/H]<$-$2.0) stars, and over 25,000 extremely metal-poor (EMP; [Fe/H]<$-$3.0) stars. Moreover, distances are determined for over 20 million stars in our sample. For the over 18 million sample stars with accurate Gaia parallaxes, stellar ages are estimated by comparing with theoretical isochrones. Astrometric information is provided for the stars in our catalog, along with radial velocities for ~10% of our sample stars, taken from completed/ongoing large-scale spectroscopic surveys.

22 pages, 23 figures, 4 tables, accepted by ApJ (the data will be released at National Astronomical Data Center of China: https://doi.org/10.12149/101073)

References in corpus (32)

• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• The Radial Velocity Experiment (RAVE): first data release
• The GALAH Survey: Scientific Motivation
• The Milky Way Tomography with SDSS: II. Stellar Metallicity
• The Radial Velocity Experiment (RAVE): Fifth Data Release
• The SEGUE Stellar Parameter Pipeline. I. Description and Initial Validation Tests
• APOGEE Data and Spectral Analysis from SDSS Data Release 16: Seven Years of Observations Including First Results from APOGEE-South
• The SEGUE Stellar Parameter Pipeline. II. Validation with Galactic Globular and Open Clusters
• The SEGUE Stellar Parameter Pipeline. III. Comparison with High-Resolution Spectroscopy of SDSS/SEGUE Field Stars
• SkyMapper Southern Survey: Second Data Release (DR2)
• High-Resolution Spectroscopic Study of Extremely Metal-Poor Star Candidates from the SkyMapper Survey
• The $R$-Process Alliance: Fourth Data Release from the Search for $r$-Process-Enhanced Stars in the Galactic Halo
• The Best and Brightest Metal-Poor Stars
• The R-process Alliance: First Magellan/MIKE Release from the Southern Search for R-Process-enhanced Stars
• The metallicity spread and the age-metallicity relation of Omega Centauri
• Determination of the Local Standard of Rest using the LSS-GAC DR1
• Ages and masses of million Galactic disk main sequence turn-off and sub-giant stars from the LAMOST Galactic spectroscopic surveys
• Radial velocities for the Hipparcos-Gaia Hundred-Thousand-Proper-Motion project
• Mapping the Galactic disk with the LAMOST and Gaia Red clump sample: I: precise distances, masses, ages and 3D velocities of $\sim$ 140000 red clump stars
• Milky Way Tomography with the SkyMapper Southern Survey. II. Photometric Re-calibration of SMSS DR2
• The Photometric Metallicity and Carbon Distributions of the Milky Way's Halo and Solar Neighborhood from S-PLUS Observations of SDSS Stripe 82
• Stellar color regression: a spectroscopy based method for color calibration to a few mmag accuracy and the recalibration of Stripe 82
• Stellar Metallicities from SkyMapper Photometry II: Precise photometric metallicities of $\sim$280,000 giant stars with [Fe/H] $<-0.75$ in the Milky Way
• Milky Way tomography with the SkyMapper Southern Survey: I: Atmospheric parameters and distances of one million red giants
• Stellar loci I. Metallicity dependence and intrinsic widths
• Targeting Bright Metal-poor Stars in the Disk and Halo Systems of the Galaxy
• Stellar loci III: Photometric metallicities for half million FGK stars of Stripe 82
• Correction to the photometric colors of the Gaia Data Release 2 with the stellar color regression method
• A Blueprint for the Milky Way's Stellar Populations. III. Spatial Distributions and Population Fractions of Local Halo Stars
• Keck HIRES Spectroscopy of SkyMapper Commissioning Survey Candidate Extremely Metal-Poor Stars
• A Blueprint for the Milky Way's Stellar Populations. II. Improved Isochrone Calibration in the SDSS and Pan-STARRS Photometric Systems

Cited by in corpus (20)

• Gaia Data Release 3: Apsis II -- Stellar Parameters
• Gaia Data Release 3: The Galaxy in your preferred colours. Synthetic photometry from Gaia low-resolution spectra
• The Pristine survey -- XXIII. Data Release 1 and an all-sky metallicity catalogue based on Gaia DR3 BP/RP spectro-photometry
• The Complexity of the Cetus Stream Unveiled from the Fusion of STREAMFINDER and StarGO
• J-PLUS: Stellar Parameters, C, N, Mg, Ca and [α/Fe] Abundances for Two Million Stars from DR1
• Dynamically Tagged Groups of Metal-Poor Stars II. The Radial Velocity Experiment Data Release 6
• Photometric recalibration of the SDSS Stripe 82 to a few milimagnitude precision with the stellar color regression method and Gaia EDR3
• Candidate Members of the VMP/EMP Disk System of the Galaxy from the SkyMapper and SAGES Surveys
• Gaia's brightest very metal-poor (VMP) stars. Metallicity catalogue of a thousand VMP stars from Gaia's radial velocity spectrometer spectra
• On the likelihoods of finding very metal-poor (and old) stars in the Milky Way's disc, bulge, and halo
• The S-PLUS Ultra-Short Survey: first data release
• A machine learning approach to photometric metallicities of giant stars
• Stellar Loci VI: An Updated Catalog of the Best and Brightest Metal-poor Stars
• Chemodynamical Properties and Ages of Metal-Poor Stars in S-PLUS
• Exploring the ex-situ components within Gaia DR3
• The Pristine Survey -- XXVII. Journey to the Galactic outskirts -- Mapping the outer halo red giant stars down to the very metal-poor end
• The Pristine survey: XXVII. The extremely metal-poor stream C-19 stretches over more than 100 degrees
• The miniJPAS survey: stellar atmospheric parameters from 56 optical filters
• Recent Advances in Understanding R-Process Nucleosynthesis in Metal-Poor Stars and Stellar Systems
• Revisiting the Galactic age-metallicity relation from wide white dwarf-main-sequence binaries