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Lithium in a short-period tidally locked binary of M67: Implications for stellar evolution, Galactic Lithium evolution, and cosmologyIn open clusters, late-F stars exhibit a Li maximum (the Li 'peak' region) at lower abundance with age, which could be due either to stellar depletion or Galactic Li enrichment (or some other cause). We have observed a short-period tidally locked binary (SPTLB) on the Li peak region in the old cluster M67 to distinguish between alternatives. SPTLBs which synchronized in the early pre-main sequence would avoid the rotational mixing which, according to Yale models, may be responsible for depleting Li with age in open cluster dwarfs. We find that both components of the M67 SPTLB have a Li abundance lying about a factor of 2 or more above any other M67 single star and about a factor of 3 or more above the mean Li peak region abundance in M67. Our results suggest that the initial Li abundance in M67 is at least as high as approximately 3.0 = 12 + log (N(sub Li)/N(sub H)). Our high M67 SPTLB Li abundance and those in other clusters support the combination of Zahn's tidal circularization and the Yale rotational mixing theories and may indicate that the halo Li plateau (analogous to the cluster Li peak region) abundance has been depleted from a higher primordial value. Implications are discussed.
Document ID
19950040840
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Deliyannis, Constantine P.
(University of Hawaii, Honolulu, HI United States)
King, Jeremy R.
(University of Texas, Austin, TX United States)
Boesgaard, Ann M.
(University of Hawaii, Honolulu, HI United States)
Ryan, Sean G.
(Anglo-Australian Observatory Epping, NSW, Australia)
Date Acquired
August 16, 2013
Publication Date
October 20, 1994
Publication Information
Publication: Astrophysical Journal, Part 2 - Letters
Volume: 434
Issue: 2
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
95A72439
Funding Number(s)
CONTRACT_GRANT: NAS5-26555
CONTRACT_GRANT: NSF AST-90-16778
Distribution Limits
Public
Copyright
Other

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