High-resolution spectroscopic analysis of a large sample of Li-rich giants found by LAMOST

Abstract

The discovery of Li-rich giant has cast a new challenge for the standard stellar evolution models, and to resolve this issue, the number of this type object has been rapidly increased because of the development of worldwide surveys these days. Taking advantage of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope survey, 44 newly Li-rich giants are reported, which are confirmed with high-resolution observations. Based on the high-resolution and high signal-to-noise spectra, we derived the atmospheric parameters and elemental abundances with the spectral synthesis method. We performed a detailed analysis of their evolutionary stages, infrared excess, projected rotational velocity (v sin i), and the stellar population. We find that (1) The Li-rich giants concentrate at the evolutionary status of the red giant branch bump, red clump, and asymptotic giant branch; (2) Three of them are fast rotators and none exhibit infrared excess. Our results imply that the origins of Li enrichment are most likely to be associated with the extra mixing in the stellar interior, and the external sources maybe only make a minor contribution. Moreover, various Li-rich episodes take place at different evolutionary stages.

arXiv comment13 pages, 5 figures, accepted for publication in ApJ

References in corpus (61)

• Astropy: A Community Python Package for Astronomy
• Gaia Data Release 2. Summary of the contents and survey properties
• The Gaia mission
• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• Estimating distances from parallaxes IV: Distances to 1.33 billion stars in Gaia Data Release 2
• Elemental Abundance Survey of The Galactic Thick Disk
• Gravity modes as a way to distinguish between hydrogen- and helium-burning red giant stars
• Chemical abundances of 1111 FGK stars from the HARPS GTO planet search program.Galactic stellar populations and planets
• Determining stellar atmospheric parameters and chemical abundances of FGK stars with iSpec
• Basic physical parameters of a selected sample of evolved stars
• A Three-Dimensional Map of Milky-Way Dust
• Galactic Reddening in 3D from Stellar Photometry - An Improved Map
• Modern stellar spectroscopy caveats
• Debris disks around Sun-like stars
• The accretion of planets and brown dwarfs by giant stars -- II. solar mass stars on the red giant branch
• Cool bottom processes on the thermally-pulsing AGB and the isotopic composition of circumstellar dust grains
• Signatures of intrinsic Li depletion and Li-Na anti-correlation in the metal-poor globular cluster NGC6397
• Precise radial velocities of giant stars. III. Spectroscopic stellar parameters
• Deep Mixing of He-3: Reconciling Big Bang and Stellar Nucleosynthesis
• Accurate fundamental parameters for 23 bright solar-type stars
• Can Extra Mixing in RGB and AGB Stars Be Attributed to Magnetic Mechanisms?
• Atomic and Molecular Data for Optical Stellar Spectroscopy
• Origin of lithium enrichment in K giants
• Rapidly-rotating lithium-rich K giants: The new case of the giant PDS365
• Observable Signatures of Planet Accretion in Red Giant Stars I: Rapid Rotation and Light Element Replenishment
• On Lithium-Rich Red Giants. I. Engulfment of Sub-Stellar Companions
• On a Rapid Lithium Enrichment and Depletion of K Giant Stars
• Metal-Poor Lithium-Rich Giants in the Radial Velocity Experiment Survey
• Determination of the Local Standard of Rest using the LSS-GAC DR1
• The Role of Planet Accretion in Creating the Next Generation of Red Giant Rapid Rotators
• Lithium-Rich Giants in Globular Clusters
• Lithium-Rich Field Giants in the Sloan Digital Sky Survey
• Old puzzle, new insights: a lithium rich giant quietly burning helium in its core
• Lithium-rich giants in the Galactic thick disk
• The nature of the Li enrichment in the most Li-rich giant star
• A large and pristine sample of standard candles across the Milky Way: ~100,000 red clump stars with 3% contamination
• Deep Mixing in Evolved Stars. II. Interpreting Li Abundances in RGB and AGB Stars
• Li-rich RGB stars in the Galactic Bulge
• Enormous Li-enhancement preceding red giant phases in low-mass stars in the Milky Way halo
• Study of Lithium Rich Giants with the GALAH Spectroscopic Survey
• An Ultra-High-Resolution Survey of the Interstellar ^7Li-to-^6Li Isotope Ratio in the Solar Neighborhood
• A Lithium-Rich Red Giant Below the Clump in the Kepler Cluster, NGC 6819
• A super lithium-rich red-clump star in the open cluster Trumpler 5
• On Infrared Excesses Associated With Li-Rich K Giants
• The Gaia -ESO Survey: Lithium enrichment histories of the Galactic thick and thin disc
• Discovery of Super-Li Rich Red Giants in Dwarf Spheroidal Galaxies
• Exploring the Effects of Stellar Rotation and Wind Clearing: Debris Disks Around F Stars
• The Gaia-ESO Survey: properties of newly discovered Li-rich giants
• A New Twist In the Evolution of Low-Mass Stars
• Two new Super Li-rich core He-burning giants: A new twist to the long tale of Li enhancement in K giants
• Mass Outflow and Chromospheric Activity of Red Giant Stars in Globular Clusters II. M13 and M92
• The Puzzling Li-rich Red Giant Associated with NGC 6819
• KIC 9821622: An interesting lithium-rich giant in the Kepler field
• Low-mass lithium-rich AGB stars in the Galactic bulge: evidence for Cool Bottom Processing?
• Far-infrared study of K giants in the solar neighborhood: Connection between Li enrichment and mass-loss
• Multidimensional hydrodynamic simulations of the hydrogen injection flash
• On the serendipitous discovery of a Li-rich giant in the globular cluster NGC 362
• Tracking Advanced Planetary Systems (TAPAS) with HARPS-N. VI. HD 238914 and TYC 3318-01333-1 - two more Li-rich giants with planets
• Super lithium-rich K giant with low ${}^{12}\mathrm{C}$ to ${}^{13}\mathrm{C}$ ratio

Cited by in corpus (15)

• The Gaia-ESO Public Spectroscopic Survey: Implementation, data products, open cluster survey, science, and legacy
• Overview of the LAMOST survey in the first decade
• 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
• Population synthesis of helium white dwarf--red giant star mergers and the formation of lithium-rich giants and carbon stars
• Lithium Enrichment Signatures of Planetary Engulfment Events in Evolved Stars
• The white dwarf binary pathways survey V. The Gaia white dwarf plus AFGK binary sample and the identification of 23 close binaries
• Many Roads Lead to Lithium: Formation Pathways For Lithium-Rich Red Giants
• Hydrodynamics and survivability during post-main-sequence planetary engulfment
• Li-rich Giants in LAMOST Survey. III. The statistical analysis of Li-rich giants
• Li-rich Giants Identified from LAMOST DR8 Low-Resolution Survey
• Emission Line Galaxies in the SHARDS Frontier Fields I: Candidate Selection and the Discovery of Bursty Hα Emitters
• Distribution and evolution of Li abundance in red clump stars can be explained by the internal gravity waves
• Sub-stellar engulfment by a main sequence star: where is the lithium?
• LAMOST/HRS Spectroscopic Analysis of Two New Li-rich Giants