Old puzzle, new insights: a lithium rich giant quietly burning helium in its core

Abstract

About 1% of giant stars have been shown to have large surface Li abundances, which is unexpected according to standard stellar evolution models. Several scenarios for lithium production have been proposed, but it is still unclear why these Li-rich giants exist. A missing piece in this puzzle is the knowledge of the exact stage of evolution of these stars. Using low-and-high-resolution spectroscopic observations, we have undertaken a survey of lithium-rich giants in the Kepler field. In this letter, we report the finding of the first confirmed Li-rich core-helium-burning giant, as revealed by asteroseismic analysis. The evolutionary timescales constrained by its mass suggest that Li-production most likely took place through non-canonical mixing at the RGB-tip, possibly during the helium flash.

16 pages, 4 figures, 1 table, accepted in ApJ Letters

References in corpus (1)

• Radius determination of solar-type stars using asteroseismology: What to expect from the Kepler mission

Cited by in corpus (54)

• Ages and fundamental properties of Kepler exoplanet host stars from asteroseismology
• An ancient extrasolar system with five sub-Earth-size planets
• LAMOST observations in the Kepler field. Database of low-resolution spectra
• NGC 6819: testing the asteroseismic mass scale, mass loss, and evidence for products of non-standard evolution
• On Lithium-Rich Red Giants. I. Engulfment of Sub-Stellar Companions
• Kepler-432: a red giant interacting with one of its two long period giant planets
• Lithium-Rich Giants in Globular Clusters
• Discovery of ubiquitous lithium production in low-mass stars
• LAMOST observations in the Kepler field. II. Database of the low-resolution spectra from the five-year regular survey
• The nature of the Li enrichment in the most Li-rich giant star
• 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
• Lithium in red giant stars: Constraining non-standard mixing with large surveys in the Gaia era
• Survey of Li-rich giants among Kepler and LAMOST fields: Determination of Li-rich giants Evolutionary Phase
• Discovery of post-mass-transfer helium-burning red giants using asteroseismology
• A super lithium-rich red-clump star in the open cluster Trumpler 5
• Study of Lithium Rich Giants with the GALAH Spectroscopic Survey
• On Infrared Excesses Associated With Li-Rich K Giants
• Searching for Li-rich giants in a sample of 12 open clusters: Li enhancement in two stars with substellar companions
• The Gaia-ESO Survey: properties of newly discovered Li-rich giants
• Overview of the LAMOST-$Kepler$ project
• On the asymptotic acoustic-mode phase in red-giant stars and its dependence on evolutionary state
• Seismic probing of the first dredge-up event through the eccentric red-giant & red-giant spectroscopic binary KIC9163796
• Enhancement of Lithium in Red Clump Stars by the Additional Energy Loss Induced by New Physics
• WIYN Open Cluster Study, LXXVI. Li Evolution Among Stars of Low/Intermediate Mass: The Metal-Deficient Open Cluster, NGC 2506
• Two new Super Li-rich core He-burning giants: A new twist to the long tale of Li enhancement in K giants
• On Lithium-Rich Red Giants. II. Engulfment on the Giant Branch of Trumpler 20
• Tracking the evolution of lithium in giants using asteroseismology: Super-Li-rich stars are almost exclusively young red-clump stars
• KIC 9821622: An interesting lithium-rich giant in the Kepler field
• Far-infrared study of K giants in the solar neighborhood: Connection between Li enrichment and mass-loss
• Lithium in stellar atmospheres: observations and theory
• The Gaia-ESO survey: Lithium abundances in open cluster Red Clump stars
• Gravity mode offset and properties of the evanescent zone in red-giant stars
• On the observational characteristics of lithium-enhanced giant stars in comparison with normal red giants
• On the serendipitous discovery of a Li-rich giant in the globular cluster NGC 362
• Spectroscopic study of two new super Li rich red clump K giants
• High-resolution spectroscopic analysis of a large sample of Li-rich giants found by LAMOST
• Automated determination of g-mode period spacing of red-giant stars
• Li-rich Giants in LAMOST Survey. III. The statistical analysis of Li-rich giants
• The Gaia-ESO Survey: Inhibited extra mixing in two giants of the open cluster Trumpler 20?
• Lithium abundances and asteroseismology of red giants: understanding the evolution of lithium in giants based on asteroseismic parameters
• Super lithium-rich K giant with low ${}^{12}\mathrm{C}$ to ${}^{13}\mathrm{C}$ ratio
• HD 16771: A lithium-rich giant in the red-clump stage
• The red giant branch phase transition: Implications for the RGB luminosity function bump and detections of Li-rich red clump stars
• Are Lithium-Rich Giants Binaries? A Radial Velocity Variability Analysis of 1,400 Giants
• Lithium Inventory of 2 $M_{\odot }$ Red Clump Stars in Open Clusters: A Test of the Helium Flash Mechanism
• Distribution and evolution of Li abundance in red clump stars can be explained by the internal gravity waves
• LAMOST/HRS Spectroscopic Analysis of Two New Li-rich Giants
• Discovery of a Metal-Poor Red Giant Star with the Highest Ultra-Lithium Enhancement
• The true nature of HE0057-5959, the most metal-poor Li-rich star
• Unevolved Li-rich stars at low metallicity: a possible formation pathway through novae
• Concerning Li-rich status of KIC~9821622: A Kepler field RGB star reported as Li-rich Giant
• The SAGA so far: reading the history of the Galaxy with asteroseismology