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/HIRESspectroscopy to measure the Li abundance in the components of
the1 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 6450 K primary and secondary
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 NGC 752 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 ofinitial Li with
metallicity inferred from nearby disk stars, open clusters, and recent Galactic
chemical evolution models are correct. Our results suggest, independently of
complementary 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.Comment: Accepted for publication in Publications of the Astronomical Society
of the Pacific (July 2013 volume
