KIC 9821622: An interesting lithium-rich giant in the Kepler field

Abstract

We report the discovery of a new exceptional young lithium-rich giant, KIC 9821622, in the \textit{Kepler} field that exhibits an unusually large enhancement of $\alpha$, Fe-peak, and \textit{r}-process elements. From high-resolution spectra obtained with GRACES at Gemini North, we derived fundamental parameters and detailed chemical abundances of 23 elements from equivalent widths and synthesis analysis. By combining atmospheric stellar parameters with available asteroseismic data, we obtained the stellar mass, radius, and age. The data analysis reveals that KIC 9821622 is a Li-rich (A(Li)${}_{NLTE}$ = 1.80 $\pm$ 0.2) intermediate-mass giant star ($M$ = 1.64 $M_{\odot }$) located at the red giant branch near the luminosity bump. We find unexpectedly elevated abundances of Fe-peak and \textit{r}-process elements. In addition, as previously reported, we find that this is a young star (2.37 Gyr) with unusually high abundances of $\alpha$-elements ([$\alpha$/Fe] = 0.31). The evolutionary status of KIC 9821622 suggests that its Li-rich nature is the result of internal fresh Li that is synthesized through the Cameron-Fowler mechanism near the luminosity bump. However, its peculiar enhancement of $\alpha$, Fe-peak, and \textit{r}-process elements opens the possibility of external contamination by material enriched by a supernova explosion. Although it is less likely, planet accretion cannot be ruled out.

arXiv commentLetter, 6 pages, 3 figures, Accepted for publication in A&A. - Some language editing included

References in corpus (36)

• The chemical composition of the Sun
• Gravity modes as a way to distinguish between hydrogen- and helium-burning red giant stars
• Basic physical parameters of a selected sample of evolved stars
• Spin down of the core rotation in red giants
• Scaled solar tracks and isochrones in a large region of the Z-Y plane I. From the ZAMS to the TP-AGB end for 0.15 - 2.5 Mo stars
• Abundances, Stellar Parameters, and Spectra From the SDSS-III/APOGEE Survey
• The APOKASC Catalog: An Asteroseismic and Spectroscopic Joint Survey of Targets in the Kepler Fields
• Departures from LTE for neutral Li in late-type stars
• The accretion of planets and brown dwarfs by giant stars -- II. solar mass stars on the red giant branch
• Asteroseismic classification of stellar populations among 13000 red giants observed by Kepler
• ARES v2 - new features and improved performance
• Mixed modes in red giants: a window on stellar evolution
• Stellar Parameters and Elemental Abundances of Late-G Giants
• Young [$\alpha$/Fe]-enhanced stars discovered by CoRoT and APOGEE: What is their origin?
• Bayesian distances and extinctions for giants observed by Kepler and APOGEE
• Stellar parameters and chemical abundances of 223 evolved stars with and without planets
• Origin of lithium enrichment in K giants
• Observable Signatures of Planet Accretion in Red Giant Stars I: Rapid Rotation and Light Element Replenishment
• On a Rapid Lithium Enrichment and Depletion of K Giant Stars
• Initial data release of the Kepler-INT Survey
• Metal-Poor Lithium-Rich Giants in the Radial Velocity Experiment Survey
• Old puzzle, new insights: a lithium rich giant quietly burning helium in its core
• Lithium-rich giants in the Galactic thick disk
• The lithium abundances for a large sample of red giants
• BD+48 740 - Li overabundant giant star with a planet. A case of recent engulfment?
• Three Li-rich K giants: IRAS 12327-6523, IRAS 13539-4153, and IRAS 17596-3952
• Zirconium, Barium, Lanthanum and Europium Abundances in Open Clusters
• The Penn State - Torun Centre for Astronomy Planet Search stars. II. Lithium abundance analysis of the Red Giant Clump sample
• Lithium abundances along the RGB: FLAMES-GIRAFFE spectra of a large sample of low-mass Bulge stars
• On Infrared Excesses Associated With Li-Rich K Giants
• Lithium abundances and extra mixing processes in evolved stars of M67
• Chemical abundances and kinematics of 257 G-, K-type field giants. Setting a base for further analysis of giant-planet properties orbiting evolved stars
• A New Twist In the Evolution of Low-Mass Stars
• Chemical compositions of thin-disk, high-metallicity red horizontal-branch field stars
• TAPAS - Tracking Advanced Planetary Systems with HARPS-N. II. Super Li-rich giant HD 107028
• High-resolution abundance analysis of HD 140283

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• On Lithium-Rich Red Giants. I. Engulfment of Sub-Stellar Companions
• Cannibals in the thick disk: the young $\alpha -$rich stars as evolved blue stragglers
• GRACES observations of young [alpha/Fe]-rich stars
• 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
• Population synthesis of helium white dwarf--red giant star mergers and the formation of lithium-rich giants and carbon stars
• The Gaia-ESO Survey: properties of newly discovered Li-rich giants
• Seismic probing of the first dredge-up event through the eccentric red-giant & red-giant spectroscopic binary KIC9163796
• Cannibals in the thick disk II -- Radial-velocity monitoring of the young alpha-rich stars
• Two new Super Li-rich core He-burning giants: A new twist to the long tale of Li enhancement in K giants
• Spectroscopic study of two new super Li rich red clump K giants
• On the observational characteristics of lithium-enhanced giant stars in comparison with normal red giants
• Optical high-resolution spectroscopy of 14 young $\alpha$-rich stars
• The Active Chromospheres of Lithium-Rich Red Giant Stars
• High-resolution spectroscopic analysis of a large sample of Li-rich giants found by LAMOST
• A search for transit timing variations and orbital decay in WASP-46b
• HD 16771: A lithium-rich giant in the red-clump stage
• Gemini-GRACES high-quality spectra of Kepler evolved stars with transiting planets I. Detailed characterization of multi-planet systems Kepler-278 and Kepler-391
• Discovery of a Metal-Poor Red Giant Star with the Highest Ultra-Lithium Enhancement
• 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