NOAO >   Observing Info >   Approved Programs >   2006B-0303

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Proposal Information for 2006B-0303


PI: Simon C. Schuler, Clemson University, sschule@ces.clemson.edu
Address: Physics Department, 118 Kinard Laboratory, Clemson, SC 29634-0978, USA

CoI: Constantine P. Deliyannis, Indiana University
CoI: Jeremy R. King, Clemson University
CoI: Styliani Kafka, NOAO/CTIO
CoI: Sydney Barnes, Lowell Observatory

Title: The Striking Li Dispersions in Pleiades G & K Dwarfs: Real or Illusory?

Abstract: The vexing problem of the enormous Li dispersion observed in the Pleiades G & K dwarfs continues to confound us more than 20 years after its initial discovery. It remains unclear if the dispersion is a result of real Li abundance differences, possibly due to rotational effects, or if it is illusory, perhaps related to chromospheric activity and/or photospheric spots. It is critically important to distinguish between these two scenarios, or the uncertainty will seriously restrict the irreplaceable use of Li as a probe of stellar interiors in young G & K dwarfs. We propose a combined long- and short-term program that will definitively determine whether activity and/or spots affect Li line strengths, and if they do, to quantify the degree of the effect. The long-term project will use WIYN 3.5m/Hydra to monitor efficiently and simultaneously the (lambda) 6707 \ionLi1 feature, the similarly formed (lambda) 7699 \ionK1 feature, and activity indicators in 43 G & K Pleiades dwarfs over a five year period, looking for possible correlated variations. The short-term project will utilize both WIYN 3.5m/Hydra and WIYN 0.9m/MOSAIC to look for line variations and correlated photometric variations, which are good indicators of spots, over a short period of four nights.


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