NOAO >   Observing Info >   Approved Programs >   2017B-0248

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Program Information for 2017B-0248


PI: Donald B Lee-Brown, U. of Kansas, donald@ku.edu
Address: Physics Department, 1251 Wescoe Hall Drive, Lawrence, KS 66045-7582 USA

CoI: Bruce A Twarog, U. of Kansas
CoI: Barbara Anthony-Twarog, U. of Kansas

Title: The Lithium Plateau in Metal-Rich Stars

Abstract: The enduring disagreement between models of cosmological nucleosynthesis and observations of Li in old, metal-poor halo dwarfs reflects deficiencies in our understanding of the Big Bang and/or stellar structure. Recent observations indicate that in younger, solar- metallicity stars, Li is asymptotically depleted in stars with temperatures 5900 K $< T_{eff} <$ 6300 K to a level nearly identical to that observed in the cosmologically important halo dwarfs. We propose to investigate whether or not this “Li plateau” extends to metal- rich stars. Compared to solar-metallicity stars, stars with [Fe/H]$geq +0.20$ have initial Li abundances that are greater by a factor of $sim 2-3$. If the metal-rich stars also asymptotically deplete their Li to the halo dwarf level, the implication is that some unknown mechanism drives a universal Li plateau across a wide range in [Fe/H]. This would make a strong case for a depleted Li abundance value in halo dwarfs, and provide important experimental constraints on future models of stellar structure.

Program Type: Standard/Galactic

Scheduled Nights:
Run 1 (2017B):  WIYN/HYDR -- 1n on Oct 30 - Oct 31 2017


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NOAO >   Observing Info >   Approved Programs >   2017B-0248

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