NOAO >   Observing Info >   Approved Programs >   2011A-0348

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Proposal Information for 2011A-0348


PI: Leslie Hebb, Vanderbilt University, leslie.hebb@vanderbilt.edu
Address: Department of Physics and Astronomy, 6301 Stevenson Center, Nashville, TN 37235, USA

CoI: Keivan Stassun, Vanderbilt University
CoI: Don Pollacco, Queen's University Belfast
CoI: Andrew Collier-Cameron, University of St Andrews
CoI: John Barnes, University of Hertfordshire
CoI: Joshua Pepper, Vanderbilt University

Title: Defining the M dwarf Mass-Radius relation as a function of activity and metallicity

Abstract: Recently, it has been established that there is a discrepancy between measured radii of M dwarf stars and their corresponding theoretical predictions. The cause of this discrepancy is likely due to magnetic activity and/or metallicity effects. Thus, our goal with this proposal is to establish in detail how M dwarf radii depend on activity and metallicity. We will empirically determine the mass-radius relationship of M dwarf stars with large number statistics over the entire M dwarf range (0.08 < M < 0.55 M_\odot) using a sample of F/G/K+M dwarf eclipsing binaries for which metallicity and activity measures can be determined. Specifically, we propose to obtain 1) a single high signal-to-noise, high resolution spectrum of all our northern hemisphere targets in order to derive the effective temperatures and metallicities via spectral synthesis of the F/G/K primary stars, 2) multiple H-band spectra to derive radial velocity curves for systems that still lack these data, and 3) multi-band eclipse light curves of our southern hemisphere objects needed to derive accurate radii. The ultimate result of this program will be to establish the effect of metallicity and activity on the radii of low- mass stars with large number statistics, over the entire M dwarf regime across the fully convective boundary and down to the hydrogen burning limit.


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