Li-rich Giants Identified from LAMOST DR8 Low-Resolution Survey

Abstract

A small fraction of giants possess photospheric lithium(Li) abundance higher than the value predicted by the standard stellar evolution models, and the detailed mechanisms of Li enhancement are complicated and lack a definite conclusion. In order to better understand the Li enhancement behaviors, a large and homogeneous Li-rich giants sample is needed. In this study, we designed a modified convolutional neural network model called Coord-DenseNet to determine the A(Li) of Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) low-resolution survey (LRS) giant spectra. The precision is good on the test set: MAE=0.15 dex, and σ=0.21 dex. We used this model to predict the Li abundance of more than 900,000 LAMOST DR8 LRS giant spectra and identified 7,768 Li-rich giants with Li abundances ranging from 2.0 to 5.4 dex, accounting for about 1.02% of all giants. We compared the Li abundance estimated by our work with those derived from high-resolution spectra. We found that the consistency was good if the overall deviation of 0.27 dex between them was not considered. The analysis shows that the difference is mainly due to the high A(Li) from the medium-resolution spectra in the training set. This sample of Li-rich giants dramatically expands the existing sample size of Li-rich giants and provides us with more samples to further study the formation and evolution of Li-rich giants.

14 pages,13 figures

References in corpus (18)

• Primordial Nucleosynthesis in the Precision Cosmology Era
• Systematic non-LTE study of the $-2.6\le$ [Fe/H] $\le 0.2$ F and G dwarfs in the solar neighbourhood. II. Abundance patterns from Li to Eu
• Observable Signatures of Planet Accretion in Red Giant Stars I: Rapid Rotation and Light Element Replenishment
• The lithium abundances for a large sample of red giants
• Lithium-rich Giants in LAMOST Survey. I. The Catalog
• Most Lithium-rich Low-mass Evolved Stars Revealed as Red Clump stars by Asteroseismology and Spectroscopy
• The Gaia-ESO Survey: Galactic evolution of lithium from iDR6
• Survey of Li-rich giants among Kepler and LAMOST fields: Determination of Li-rich giants Evolutionary Phase
• Enormous Li-enhancement preceding red giant phases in low-mass stars in the Milky Way halo
• The Penn State - Torun Centre for Astronomy Planet Search stars. II. Lithium abundance analysis of the Red Giant Clump sample
• Study of Lithium Rich Giants with the GALAH Spectroscopic Survey
• Population synthesis of helium white dwarf--red giant star mergers and the formation of lithium-rich giants and carbon stars
• Discovery of Super-Li Rich Red Giants in Dwarf Spheroidal Galaxies
• Time of primordial Be-7 conversion into Li-7, energy release and doublet of narrow cosmological neutrino lines
• High-resolution spectroscopic analysis of a large sample of Li-rich giants found by LAMOST
• The Lithium Abundances from the Large Sky Area Multi-object Fiber Spectroscopic Telescope Medium-resolution Survey. I. The Method
• Lithium abundances in the old open cluster NGC 3960 from VLT/FLAMES observations
• Li-rich and super Li-rich giants produced by element diffusion

Cited by in corpus (3)

• Estimating Stellar Parameters from LAMOST Low-resolution Spectra
• Are Lithium-Rich Giants Binaries? A Radial Velocity Variability Analysis of 1,400 Giants
• Discovery of a Metal-Poor Red Giant Star with the Highest Ultra-Lithium Enhancement