WIYN Open Cluster Study: The Old Open Cluster, NGC 188, and a Re-evaluation of Lithium-Richness Among Red Giants

Abstract

We present WIYN/Hydra spectra of 34 red giant candidate members of NGC 188, which, together with WOCS and Gaia data yield 23 single members, 6 binary members, 4 single nonmembers, and 1 binary nonmember. We report [Fe/H] for 29 members and derive [Fe/H]${}_{NGC188}$ = +0.064 $\pm$ 0.018 dex (${\sigma }_{\mu }$) (sky spectra yield A(Fe)${}_{\odot }$ = 7.520 $\pm$ 0.015 dex (${\sigma }_{\mu }$)). We discuss effects on the derived parameters of varying Yale-Yonsei isochrones to fit the turnoff. We take advantage of the coolest, lowest-gravity giants to refine the line list near Li 6707.8 Å. Using synthesis we derive detections of A(Li) = 1.17, 1.65, 2.04, and 0.60 dex for stars 4346, 4705, 5027, and 6353, respectively, and 3$\sigma$ upper-limits for the other members. Whereas only two of the detections meet the traditional criterion for "Li-richness" of A(Li) > 1.5 dex, we argue that since the cluster A(Li) vanish as subgiants evolve to the base of the RGB, all four stars are Li-rich in this cluster's context. An incidence of even a few Li-rich stars in a sample of 29 stars is far higher than what recent large surveys have found in the field. All four stars lie either slightly or substantially away from the cluster fiducial sequence, possibly providing clues about their Li-richness. We discuss a number of possibilities for the origin for the Li in each star, and suggest potentially discriminating future observations.

arXiv comment20 pages, 16 figures, 7 tables, accepted for publication in MNRAS

References in corpus (71)

• Gaia Data Release 2. Summary of the contents and survey properties
• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• The Man Behind the Curtain: X-rays Drive the UV through NIR Variability in the 2013 AGN Outburst in NGC 2617
• A Gaia DR2 view of the Open Cluster population in the Milky Way
• The effective temperature scale of FGK stars. II. Teff : color : [Fe/H] calibrations
• Nucleosynthesis in Classical Novae: ONe vs. CO White Dwarfs
• Some Revised Observational Constraints on the Formation and Evolution of the Galactic Disk
• Thermohaline instability and rotation-induced mixing. I - Low- and intermediate-mass solar metallicity stars up to the end of the AGB
• The accretion of planets and brown dwarfs by giant stars -- II. solar mass stars on the red giant branch
• On the metallicity of open clusters. III. Homogenised sample
• A Complete Survey of Case A Binary Evolution with Comparison to Observed Algol-Type Systems
• The ASAS-SN Catalog of Variable Stars II: Uniform Classification of 412,000 Known Variables
• Standard big bang nucleosynthesis and primordial CNO Abundances after Planck
• The Gaia FGK Benchmark Stars - High resolution spectral library
• Origin of lithium enrichment in K giants
• A Chemical Abundance Study of 10 Open Clusters Based on WIYN-Hydra Spectroscopy
• WIYN Open Cluster Study XXXII: Stellar Radial Velocities in the Old Open Cluster NGC 188
• WIYN Open Cluster Study. LXXV. Testing the Metallicity Dependence of Stellar Lithium Depletion Using Hyades-Aged Clusters. 1. Hyades & Praesepe
• Magnetic Inhibition of Convection and the Fundamental Properties of Low-Mass Stars. II. Fully Convective Main Sequence Stars
• On the metallicity of open clusters II. Spectroscopy
• 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
• Iron abundances from high-resolution spectroscopy of the open clusters NGC 2506, NGC 6134, and IC 4651
• Rotation, inflation, and lithium in the Pleiades
• Galactic chemical evolution of Lithium: interplay between stellar sources"
• The catalogue of radial velocity standard stars for Gaia I. Pre-launch release
• Tidal interactions between binary stars drives lithium production in low-mass red giants
• Implications for the Formation of Blue Straggler Stars from HST Ultraviolet Observations of NGC 188
• Beryllium in the Hyades F and G Dwarfs from Keck/HIRES Spectra
• WIYN Open Cluster Study. XVII. Astrometry and Membership to V=21 in NGC 188
• Blue Stragglers After the Main Sequence
• On the Numerical Treatment and Dependence of Thermohaline Mixing in Red Giants
• Lithium-Rich Giants in Globular Clusters
• Lithium-Rich Field Giants in the Sloan Digital Sky Survey
• Discovery of ubiquitous lithium production in low-mass stars
• On the Origin of Sub-subgiant Stars. I. Demographics
• Beryllium Enhancement as Evidence for Accretion in a Lithium-Rich F Dwarf
• Lithium in the Intermediate-Age Open Cluster, NGC 3680
• The inflated radii of M-dwarfs in the Pleiades
• The Open Cluster Chemical Abundances and Mapping Survey: II. Precision Cluster Abundances for APOGEE using SDSS DR14
• Boron Depletion in F and G Dwarf Stars and the Beryllium-Boron Correlation
• Lithium-rich Giants in LAMOST Survey. I. The Catalog
• Zirconium, Barium, Lanthanum and Europium Abundances in Open Clusters
• WIYN Open Cluster Study. XXXVI. Spectroscopic Binary Orbits in NGC 188
• WIYN/Hydra Detection of Lithium Depletion in F Stars of the Young Open Cluster M35 and Implications for the Development of the Lithium Gap
• Lithium and Lithium Depletion in Halo Stars on Extreme Orbits
• Population synthesis of helium white dwarf--red giant star mergers and the formation of lithium-rich giants and carbon stars
• A Lithium-Rich Red Giant Below the Clump in the Kepler Cluster, NGC 6819
• Study of Lithium Rich Giants with the GALAH Spectroscopic Survey
• The effects of rotation on the lithium depletion of G- and K-dwarfs in Messier 35
• Evolution of lithium beyond the solar age: a Li survey of the old open cluster NGC 188
• OCCASO II. Physical parameters and Fe abundances of Red Clump stars in 18 Open Clusters
• Searching for Li-rich giants in a sample of 12 open clusters: Li enhancement in two stars with substellar companions
• Boron Abundances Across the "Li-Be Dip" in the Hyades
• Li Evolution and the Open Cluster NGC 6819: A Correlation Between Li Depletion and Spindown in Dwarfs More Massive Than the F-Dwarf Li-Dip
• The Gaia-ESO Survey: Stellar radii in the young open clusters NGC 2264, NGC 2547 and NGC 2516
• The K2 M67 Study: An Evolved Blue Straggler in M67 from K2 Mission Asteroseismology
• Constraining Mass Transfer Histories of Blue Straggler Stars with COS Spectroscopy of White Dwarf Companions
• A New Twist In the Evolution of Low-Mass Stars
• Explaining the decrease in ISM lithium at super-solar metallicities in the solar vicinity
• WIYN Open Cluster Study, LXXVI. Li Evolution Among Stars of Low/Intermediate Mass: The Metal-Deficient Open Cluster, NGC 2506
• The Puzzling Li-rich Red Giant Associated with NGC 6819
• The Gaia-ESO survey: Lithium abundances in open cluster Red Clump stars
• A search for radius inflation among active M-dwarfs in Praesepe
• Abundance analyses of Li-enriched and normal giants in the GALAH survey
• WIYN Open Cluster Study LXXIX. M48 (NGC 2548) I. Radial Velocities, Rotational Velocities, and Metallicities of Stars in the Open Cluster M48 (NGC 2548)
• Lithium Evolution of Giant Stars Observed by LAMOST and Kepler
• WIYN Open Cluster Study LXXXV. Li in NGC 2243 -- Implications for Stellar and Galactic Evolution
• A Chandra X-ray census of the interacting binaries in old open clusters - NGC188
• WIYN Open Cluster Study LXXXI. Caught in the Act? The Peculiar Red Giant NGC 2243-W2135

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