NOAO >   Observing Info >   Approved Programs >   2006A-0328

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Proposal Information for 2006A-0328


PI: David C. Knauth, Northwestern University, d-knauth@northwestern.edu
Address: Physics Department, 2145 Sheridan Road, Evanston, IL 60208, United States

CoI: David M. Meyer, Northwestern University
CoI: James T. Lauroesch, Northwestern University

Title: The Interstellar ^7Li/^6Li Isotope Ratio towards the Star-forming Cluster NGC 6231

Abstract: Our previous high-resolution study of the ^7Li/^6Li isotope ratio toward 5 stars suggests that a ratio ~ 12 pervades the gas in the Solar neighborhood. The lone exception is the line of sight toward o Per, which shows a ratio of ~ 2, the value expected from Li production due to GCR spallation reactions. The low isotope ratio toward o Per was explained by ^6Li production resulting from an enhanced flux of cosmic rays originating from the nearby star-forming region IC 348. Here we propose observations of the ^7Li/^6Li isotope ratio toward the star-forming cluster NGC 6231 in the Sco OB1 Association to investigate if similar processes are occurring. Recent high-resolution observations of the strong K I (lambda)7698 and CH (lambda)4300 absorption toward HD 152235 and HD 152236 reveal a substantial varying amount of neutral atomic and molecular absorption. Through high S/N (~ 2000 per pixel) observations of interstellar Li \small I and K \small I toward these three stars, we plan to probe the homogeneity of the ^7Li/^6Li isotope ratio in this region.


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NOAO >   Observing Info >   Approved Programs >   2006A-0328

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