NOAO >   Observing Info >   Approved Programs >   2006B-0099

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Proposal Information for 2006B-0099


PI: Keivan G. Stassun, Vanderbilt University, keivan.stassun@vanderbilt.edu
Address: Physics Department, VU Station B 1807, Nashville, TN 37235, USA

CoI: David J. James, Vanderbilt University
CoI: Josefina Montalban, l'Universite de Liege, Belgium
CoI: Rob Jeffries, Keele University, England

Title: Testing Stellar Interiors Models and Calibrating Age Determinations for Pre-Main-Sequence Stars

Abstract: We will obtain high-resolution echelle spectra of six low-mass pre- main-sequence (PMS) stars in the Taurus-Auriga star-forming region. The stars in our sample represent all of the single, low-mass PMS stars whose masses have been measured empirically and accurately. As such, these stars are key benchmarks for testing and calibrating models of PMS stellar evolution. \it We will use these observations to make precise measurements of the surface abundance of lithium in these six stars. Li is a delicate chemical species that is destroyed as it is convectively mixed from the surface to the interior. Our aim is to constrain key physical parameters of PMS stellar interiors-the temperature profile at the interior/atmosphere interface, the temperature profile of the convection zone, and the efficiency of convective mixing-upon which the predictions of PMS stellar evolution models depend sensitively. Li also provides an independent measure of stellar ages, and thereby serves as a critical internal consistency check on ages derived via model isochrones in the H-R diagram. This experiment is an important facet of a broader program to make accurate measurements of fundamental physical properties of young stars, and to use these measurements to test and calibrate models of PMS stellar evolution with respect to mass and age.


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