Estimating Stellar Atmospheric Parameters and [α/Fe] for LAMOST O-M type Stars Using a Spectral Emulator

Abstract

In this paper, we developed a spectral emulator based on the Mapping Nearby Galaxies at Apache Point Observatory Stellar Library (MaStar) and a grouping optimization strategy to estimate effective temperature (T_eff), surface gravity (log g), metallicity ([Fe/H]) and the abundance of alpha elements with respect to iron ([alpha/Fe]) for O-M-type stars within the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) low-resolution spectra. The primary aim is to use a rapid spectral-fitting method, specifically the spectral emulator with the grouping optimization strategy, to create a comprehensive catalog for stars of all types within LAMOST, addressing the shortcomings in parameter estimations for both cold and hot stars present in the official LAMOST AFGKM-type catalog. This effort is part of our series of studies dedicated to establishing an empirical spectral library for LAMOST. Experimental results demonstrate that our method is effectively applicable to parameter prediction for LAMOST, with the single-machine processing time within $70$ hr. We observed that the internal error dispersions for T_eff, log g, [Fe/H], and [alpha/Fe] across different spectral types lie within the ranges of $15-594$ K, $0.03-0.27$ dex, $0.02-0.10$ dex, and $0.01-0.04$ dex, respectively, indicating a good consistency. A comparative analysis with external data highlighted deficiencies in the official LAMOST catalog and issues with MaStar parameters, as well as potential limitations of our method in processing spectra with strong emission lines and bad pixels. The derived atmospheric parameters as a part of this work are available at https://nadc.china-vo.org/res/r101402/ .

34 pages, 28 Figures, published in ApJS

References in corpus (25)

• Array Programming with NumPy
• The Astropy Project: Sustaining and Growing a Community-oriented Open-source Project and the Latest Major Release (v5.0) of the Core Package
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• The 2.5 m Telescope of the Sloan Digital Sky Survey
• 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
• APOGEE Data and Spectral Analysis from SDSS Data Release 16: Seven Years of Observations Including First Results from APOGEE-South
• Target Selection for the SDSS-IV APOGEE-2 Survey
• A Catalog of Diffuse Interstellar Bands in the Spectrum of HD 204827
• PARSEC V2.0: Stellar tracks and isochrones of low and intermediate mass stars with rotation
• The LAMOST Stellar Parameter Pipeline at Peking University --- LSP3
• Estimating stellar atmospheric parameters, absolute magnitudes and elemental abundances from the LAMOST spectra with Kernel-based Principal Component Analysis
• Overview of the LAMOST survey in the first decade
• LAMOST Spectroscopic Survey of the Galactic Anticentre (LSS-GAC): the second release of value-added catalogues
• The extended halo of NGC 2682 (M 67) from Gaia DR2
• LAMOST meets Gaia: The Galactic Open Clusters
• Stellar parametrization of LAMOST M dwarf stars
• The Gaia-ESO Survey: The analysis of the hot-star spectra
• SDSS-IV MaStar: Data-driven Parameter Derivation for the MaStar Stellar Library
• Cool and Data-Driven: An Exploration of Optical Cool Dwarf Chemistry with Both Data-Driven and Physical Models
• Atmospheric parameters and kinematic information for the M giants stars from LAMOST DR9
• SDSS-IV MaStar: Stellar Parameter Determination with Continuum-Supplemented Full-Spectrum Fitting
• Study on Outliers in the Big Stellar Spectral Dataset of the Fifth Data Release (DR5) of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST)