Lithium Abundances In Nearby FGK Dwarf And Subgiant Stars: Internal Destruction, Galactic Chemical Evolution, And Exoplanets

dc.contributor.utaustinauthorRamirez, Ivanen_US
dc.contributor.utaustinauthorLambert, David L.en_US
dc.creatorRamirez, Ivanen_US
dc.creatorFish, J. R.en_US
dc.creatorLambert, David L.en_US
dc.creatorPrieto, Carlos Allendeen_US
dc.description.abstractWe derive atmospheric parameters and lithium abundances for 671 stars and include our measurements in a literature compilation of 1381 dwarf and subgiant stars. First, a "lithium desert" in the effective temperature (T-eff) versus lithium abundance (A(Li)) plane is observed such that no stars with T-eff similar or equal to 6075 K and A(Li) similar or equal to 1.8 are found. We speculate that most of the stars on the low ALi side of the desert have experienced a short-lived period of severe surface lithium destruction as main-sequence or subgiant stars. Next, we search for differences in the lithium content of thin-disk and thick-disk stars, but we find that internal processes have erased from the stellar photospheres their possibly different histories of lithium enrichment. Nevertheless, we note that the maximum lithium abundance of thick-disk stars is nearly constant from [Fe/H] = -1.0 to -0.1, at a value that is similar to that measured in very metal-poor halo stars (A(Li) similar or equal to 2.2). Finally, differences in the lithium abundance distribution of known planet-host stars relative to otherwise ordinary stars appear when restricting the samples to narrow ranges of T-eff or mass, but they are fully explained by age and metallicity biases. We confirm the lack of a connection between low lithium abundance and planets. However, we find that no low A(Li) planet-hosts are found in the desert T-eff window. Provided that subtle sample biases are not responsible for this observation, this suggests that the presence of gas giant planets inhibit the mechanism responsible for the lithium desert.en_US
dc.description.departmentMcDonald Observatoryen_US
dc.description.sponsorshipCalifornia Institute of Technology (Caltech)en_US
dc.description.sponsorshipNASA through Sagan Fellowship Programen_US
dc.description.sponsorshipCarnegie-Princeton graduate student programen_US
dc.description.sponsorshipRobert A. Welch Foundation of Houston, Texas F-634en_US
dc.identifier.citationRam�rez, I., J. R. Fish, D. L. Lambert, and C. Allende Prieto. "Lithium abundances in nearby FGK dwarf and subgiant stars: internal destruction, Galactic chemical evolution, and exoplanets." The Astrophysical Journal, Vol. 756, No. 1 (Sep., 2012): 46.en_US
dc.relation.ispartofserialAstrophysical Journalen_US
dc.rightsAdministrative deposit of works to Texas ScholarWorks: This works author(s) is or was a University faculty member, student or staff member; this article is already available through open access or the publisher allows a PDF version of the article to be freely posted online. The library makes the deposit as a matter of fair use (for scholarly, educational, and research purposes), and to preserve the work and further secure public access to the works of the University.en_US
dc.subjectplanetary systemsen_US
dc.subjectstars: abundancesen_US
dc.subjectstars: evolutionen_US
dc.subjectmain-sequence starsen_US
dc.subjectsolar-type starsen_US
dc.subjectgeneva-copenhagen surveyen_US
dc.subjectplanet-host starsen_US
dc.subjectextrasolar planetsen_US
dc.subjecty-2 isochronesen_US
dc.subjectli abundanceen_US
dc.subjectparent starsen_US
dc.subjectastronomy & astrophysicsen_US
dc.titleLithium Abundances In Nearby FGK Dwarf And Subgiant Stars: Internal Destruction, Galactic Chemical Evolution, And Exoplanetsen_US

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