The true nature of HE0057-5959, the most metal-poor Li-rich star

Abstract

The Li-rich stars are a class of rare objects with A(Li) higher than that of other stars in the same evolutionary stage. Their origin is still debated and valuable routes are the Cameron-Fowler mechanism, mass transfer process in a binary system or engulfment of small bodies. Metal-poor ([Fe/H]<-1 dex) stars are only a small fraction of the entire population of Li-rich stars. We observed with MIKE at the Magellan Telescope the metal-poor ([Fe/H]=-3.95+-0.11 dex) giant star HE0057-5959, deriving A(Li)=+2.09+-0.07 dex. Such A(Li) is higher by about 1 dex than that of other stars in the same evolutionary stage. A previous analysis of the same target suggested that its high A(Li) reflects a still ongoing First Dredge-Up process. We revise the nature of HE0057-5959 by comparing its stellar parameters and A(Li) with appropriate stellar evolution models. This comparison rules out that HE0057-5959 is caught during its First Dredge-Up, being this latter already ended according to the parameters of this star. Its A(Li), remarkably higher than the typical lithium plateau drawn by similar giant stars, demonstrates that HE0057-5959 joins the class of the rare metal-poor Li-rich stars. HE0057-5959 is the most metal-poor Li-rich star discovered so far. We consider different scenarios to explain this star. No internal mixing able to activate the Cameron-Fowler mechanism is known for metal-poor stars at this evolutionary stage. Also the engulfment of planets is disfavored because such metal-poor stars should not host planets. Finally, HE0057-5959 is one of the most Na-rich among the Li-rich stars and we found that a strong excess of Na is common to the three Li-rich stars with [Fe/H]<-3 dex. This finding could support the scenario of mass transfer from a massive companion star in a binary system, even if we found no evidence of radial velocity variations.

arXiv commentAccepted for publication in A&A

References in corpus (93)

• The chemical composition of the Sun
• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• The Gaia mission
• The Transiting Exoplanet Survey Satellite
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• Solar Chemical Abundances Determined with a CO5BOLD 3D Model Atmosphere
• Giant Planet Occurrence in the Stellar Mass-Metallicity Plane
• Multiple Stellar Populations in Globular Clusters
• Optimal Techniques in Two-dimensional Spectroscopy: Background Subtraction for the 21st Century
• A Search for Stars of Very Low Metal Abundance. VI. Detailed Abundances of 313 Metal-Poor Stars
• Lithium isotopic abundances in metal-poor halo stars
• Non-LTE calculations for neutral Na in late-type stars using improved atomic data
• The Most Metal-Poor Stars. II. Chemical Abundances of 190 Metal-Poor Stars Including 10 New Stars With [Fe/H] < -3.5
• The Spite Lithium Plateau: Ultra-Thin but Post-Primordial
• Solar System Abundances of the Elements
• The accretion of planets and brown dwarfs by giant stars -- II. solar mass stars on the red giant branch
• The primordial lithium abundance
• Signatures of intrinsic Li depletion and Li-Na anti-correlation in the metal-poor globular cluster NGC6397
• Updated Gaia-2MASS 3D maps of Galactic interstellar dust
• The updated BaSTI stellar evolution models and isochrones: II. alpha-enhanced calculations
• TOPoS: II. On the bimodality of carbon abundance in CEMP stars. Implications on the early chemical evolution of galaxies
• Lithium Abundances of Extremely Metal-Poor Turn-off Stars
• Evolved stars hint to an external origin of enhanced metallicity in planet-hosting stars
• Evolution and nucleosynthesis of asymptotic giant branch stellar models of low metallicity
• NLTE determination of the sodium abundance in a homogeneous sample of extremely metal-poor stars
• Non-LTE aluminium abundances in late-type stars
• Carbon-Enhanced Metal-Poor Stars. III. Main-Sequence Turn-Off Stars from the SDSS/SEGUE Sample
• Stellar Archaeology: a Keck Pilot Program on Extremely Metal- Poor Stars From the Hamburg/ESO Survey. III. The Lead (Pb) Star HE 0024-2523
• The Lithium Content of the Galactic Halo Stars
• High-Resolution Spectroscopic Study of Extremely Metal-Poor Star Candidates from the SkyMapper Survey
• Red Supergiant Stars as Cosmic Abundance Probes: II. NLTE Effects in J-band Silicon Lines
• Super and massive AGB stars - III. Nucleosynthesis in metal-poor and very metal-poor stars - Z=0.001 and 0.0001
• First stars X. The nature of three unevolved Carbon-Enhanced Metal-Poor stars
• Exploiting the Gaia EDR3 photometry to derive stellar temperatures
• CS22964-161: A Double-Lined Carbon- and s-Process-Enhanced Metal-Poor Binary Star
• Primordial nucleosynthesis
• Exploring the Origin of Lithium, Carbon, Strontium and Barium with four new Ultra Metal-Poor Stars
• Near-UV Observations of CS29497-030: New Constraints on Neutron-Capture Nucleosynthesis Processes
• GALA: an automatic tool for the abundance analysis of stellar spectra
• 3D NLTE spectral line formation of lithium in late-type stars
• Early optical spectra of nova V1369 Cen show presence of Lithium
• Heavy metal rules. I. Exoplanet incidence and metallicity
• Magneto-Thermohaline Mixing in Red Giants
• The metallicity signature of evolved stars with planets
• Metal-Poor Lithium-Rich Giants in the Radial Velocity Experiment Survey
• Binarity among CEMP-no stars: an indication of multiple formation pathways?
• The Most Metal-Poor Stars. I. Discovery, Data, and Atmospheric Parameters
• Chemical Analysis of the Ninth Magnitude Carbon-Enhanced Metal-Poor Star BD+44 493
• TOPoS: IV. Chemical abundances from high-resolution observations of seven EMP stars
• Lithium abundances in CEMP stars
• Lithium-Rich Giants in Globular Clusters
• Lithium-Rich Field Giants in the Sloan Digital Sky Survey
• Lithium and sodium in the globular cluster M4. Detection of a Li-rich dwarf star: preservation or pollution?
• Old puzzle, new insights: a lithium rich giant quietly burning helium in its core
• Lithium-rich giants in the Galactic thick disk
• BD+48 740 - Li overabundant giant star with a planet. A case of recent engulfment?
• Lithium-rich Giants in LAMOST Survey. I. The Catalog
• An Extremely Lithium-Rich Bright Red Giant in the Globular Cluster M3
• The Hobby-Eberly Telescope "Chemical Abundances of Stars in the Halo" (CASH) Project. I. The Lithium-, s-, and r-Enhanced Metal-Poor Giant HKII 17435-00532
• High-resolution spectroscopic studies of ultra metal-poor stars found in LAMOST survey
• 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
• Li-rich RGB stars in the Galactic Bulge
• Giants reveal what dwarfs conceal: Li abundance in lower RGB stars as diagnostic of the primordial Li
• J0023+0307: A mega metal-poor dwarf star from SDSS/BOSS
• Precise radial velocities of giant stars XVI. Planet occurrence rates from the combined analysis of the Lick, EXPRESS, and PPPS giant star surveys
• The Lithium Flash - Thermal instabilities generated by lithium burning in RGB stars
• Enormous Li-enhancement preceding red giant phases in low-mass stars in the Milky Way halo
• Prospects for Galactic and stellar astrophysics with asteroseismology of giant stars in the $TESS$ Continuous Viewing Zones and beyond
• Atomic diffusion and mixing in old stars VI: The lithium content of M30
• Facing the problems on the determination of stellar temperatures and gravities: Galactic globular clusters
• A super lithium-rich red-clump star in the open cluster Trumpler 5
• Discovery of Super-Li Rich Red Giants in Dwarf Spheroidal Galaxies
• Discovery of a super-Li rich turn-off star in the metal poor globular cluster NGC 6397
• G64-12 and G64-37 are Carbon-Enhanced Metal-Poor Stars
• HIP 114328: a new refractory-poor and Li-poor solar twin
• High-resolution spectroscopy of extremely metal-poor stars from SDSS/SEGUE. III. Unevolved Stars with $[Fe/H]\lesssim -3.5$
• First detection of a lithium rich carbon star in the Draco dwarf galaxy: evidence for a young stellar population
• A Catalogue of Solar-Like Oscillators Observed by TESS in 120-second and 20-second Cadence
• Discovery of a thin lithium plateau among metal-poor red giant branch stars
• NGC 5694: another foster son of the Galactic Halo
• Evolution and nucleosynthesis of helium-rich asymptotic giant branch models
• Chemical Evolution of R-process Elements in Stars (CERES). I. Stellar parameters and chemical abundances from Na to Zr
• Models for the lithium abundances of multiple populations in globular clusters and the possible role of the Big Bang lithium
• On the serendipitous discovery of a Li-rich giant in the globular cluster NGC 362
• Planets around the evolved stars 24 Booties and $\gamma$ Libra: A 30d-period planet and a double giant-planet system in possible 7:3 MMR
• Young giants of intermediate mass Evidence of rotation and mixing
• 1D non-LTE corrections for chemical abundance analyses of very metal-poor stars
• The Gaia-ESO Survey: an extremely Li-rich giant in the globular cluster NGC 1261
• 7Be detection in the 2021 outburst of RS Oph
• Lithium in the lower red giant branch of 5 Galactic globular clusters
• The discovery of a Li-Na-rich giant star in Omega Centauri: formed from the pure ejecta of super-AGB stars?
• Curiouser and curiouser: the peculiar chemical composition of the Li/Na-rich star in Omega Centauri

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