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The evolution of the lithium abundances of solar-type stars. II - The Ursa Major GroupWe draw upon a recent study of the membership of the Ursa Major Group (UMaG) to examine lithium among 0.3 Gyr old solar-type stars. For most G and K dwarfs, Li confirms the conclusions about membership in UMaG reached on the basis of kinematics and chromospheric activity. G and K dwarfs in UMaG have less Li than comparable stars in the Pleiades. This indicates that G and K dwarfs undergo Li depletion while they are on the main sequence, in addition to any pre-main-sequence depletion they may have experienced. Moreover, the Li abundances of the Pleiades K dwarfs cannot be attributed to main-sequence depletion alone, demonstrating that pre-main-sequence depletion of Li also takes place. The sun's Li abundance implies that the main-sequence mechanism becomes less effective with age. The hottest stars in UMaG have Li abundances like those of hot stars in the Pleiades and Hyades and in T Tauris, and the two genuine UMaG members with temperatures near Boesgaard's Li chasm have Li abundances consistent with that chasm developing fully by 0.3 Gyr for stars with UMaG's metallicity. We see differences in the abundance of Li between UMaG members of the same spectral types, indicating that a real spread in the lithium abundance exists within this group.
Document ID
19930056210
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Soderblom, David R.
(Space Telescope Science Inst. Baltimore, MD, United States)
Pilachowski, Catherine A.
(Kitt Peak National Observatory Tucson, AZ, United States)
Fedele, Stephen B.
(Space Telescope Science Inst. Baltimore, MD, United States)
Jones, Burton F.
(Lick Observatory Santa Cruz, CA, United States)
Date Acquired
August 16, 2013
Publication Date
June 1, 1993
Publication Information
Publication: Astronomical Journal
Volume: 105
Issue: 6
ISSN: 0004-6256
Subject Category
Astrophysics
Accession Number
93A40207
Distribution Limits
Public
Copyright
Other

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