WIYN Open Cluster Study. LXXV. Testing the Metallicity Dependence of Stellar Lithium Depletion Using Hyades-aged Clusters. I. Hyades and Praesepe

Journal Article · Wed Mar 01 04:00:00 EST 2017 · The Astronomical Journal (Online)

DOI:https://doi.org/10.3847/1538-3881/AA5B86· OSTI ID:22863118

Cummings, Jeffrey D. ^[1]; Deliyannis, Constantine P. ^[2]; Maderak, Ryan M. ^[3]; Steinhauer, Aaron ^[4]

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1. Center for Astrophysical Sciences, Johns Hopkins University, 3400 N Charles Street, Baltimore, MD 21218 (United States)
2. Department of Astronomy, Indiana University, 727 E 3rd Street, Bloomington, IN 47405-7105 (United States)
3. Department of Physics and Astronomy, Benedictine College, 1020 N 2nd Street, Atchison, KS 66002 (United States)
4. Department of Physics and Astronomy, SUNY Geneseo, 1 College Circle, Geneseo, NY 14454 (United States)

WIYN/Hydra spectroscopy (at R ∼ 15,000) of the moderately metal-rich Praesepe and Hyades open clusters was used to study their main-sequence (MS) iron ([Fe/H]) and lithium (A(Li)) abundances. Self-consistent [Fe/H] and Li analyses of these clusters of consistent age, which we re-evaluate, confirms that they have consistent [Fe/H] and provides a foundation to investigate the poorly understood G-dwarf and F-dwarf Li-depletions. Neither phenomenon agrees with standard stellar evolution theory, but possible explanations abound. We supplement our A(Li) with previously published results placed on a uniform abundance scale. This creates the largest self-consistently analyzed sample of A(Li) in both the Hyades (90) and Praesepe (110). For each star, high-precision UBVRI photometry was used to determine a 10-color-based T{sub eff} and then to test for photometric peculiarities indicated by a large σ{sub Teff} (>75 K). The stars that have large σ{sub Teff} were predominantly found to be binaries or stars with peculiar (apparent) A(Li). When considering only proper-motion members that have low σ{sub Teff} and are also photometrically consistent with the cluster MS fiducial, each cluster has a more tightly defined Li morphology than previously observed and the two clusters’ A(Li) are indistinguishable. This suggests that clusters of consistent age and metallicity may have consistent Li-depletion trends across a broad range of T{sub eff}; no additional major parameters are required, at least for these two clusters. We propose that the combined Hyades and Praesepe data offer more rigorous constraints than does either cluster alone, and we discuss newly revealed features of the combined Li–T{sub eff} trend.

• OSTI ID: 22863118
• Journal Information: The Astronomical Journal (Online), Journal Name: The Astronomical Journal (Online) Journal Issue: 3 Vol. 153; ISSN 1538-3881
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABUNDANCE
IRON
LITHIUM
METALLICITY
PHOTOMETRY
PROPER MOTION
SPECTROSCOPY
STAR EVOLUTION
STARS