Document Type

Article

Publication Date

6-4-2013

Publication Title

Publications of the Astronomical Society of the Pacific

Volume

125

Issue

929

Publisher

Astronomical Society of the Pacific

Abstract

As a test of rotationally-induced mixing causing the well-known Li dip in older mid-F dwarfs in the local Galactic disk, we utilize high-resolution and -S/N Keck/HIRES spectroscopy to measure the Li abundance in the components of the ∼1 Gyr, [Fe/H]= −0.15 eclipsing short-period binary V505 Per. We find A(Li) ∼ 2.7 ± 0.1 and 2.4 ± 0.2 in the Teff∼6500 and 6450K primary and sec-ondary components, respectively. Previous Teff determinations and uncertainties suggest that each component is located in the midst of the Li dip. If so, their A(Li) are ≥2–5 times larger than A(Li) detections and upper limits observed in the similar metallicity and intermediate-age open clusters NGC752 and 3680, as well as the more metal-rich and younger Hyades and Praesepe. These differences are even larger if the consistent estimates of the scaling of initial Li with metal-licity inferred from nearby disk stars, open clusters, and recent Galactic chemical evolution models are correct. Our results suggest, independently of complemen-tary evidence based on Li/Be ratios, Be/B ratios, and Li in subgiants evolving out of the Li dip, that main-sequence angular momentum evolution is the origin of the Li dip. Specifically, our stars’ A(Li) indicates tidal synchronization can be sufficiently efficient and occur early enough in short-period binary mid-F stars to reduce the effects of rotationally-induced mixing and destruction of Li occuring during the main-sequence in otherwise similar stars that are not short-period tidally-locked binaries.

Comments

Published version may be found here: http://www.astrosociety.org/publications/pasp/

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