NOAO >   Observing Info >   Approved Programs >   2014A-0154

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Proposal Information for 2014A-0154


PI: Andrew Mann, University of Texas at Austin, amann@astro.as.utexas.edu
Address: The University of Texas at Austin, McDonald Observatory, 2515 Speedway, STOP C1402, Austin, Texas 78712-1206, USA

CoI: Niall Deacon, Max Planck Institute for Astronomy
CoI: Katelyn Allers, Bucknell University
CoI: John Brewer, Yale University
CoI: Eugene Magnier, University of Hawaii
CoI: Michael Liu, University of Hawaii

Title: Prospecting in Ultracool Dwarfs: Measuring the metallicity of L dwarfs

Abstract: Ultracool dwarfs (M6 and later) provide a natural link between stellar astrophysics and the planetary science of giant exoplanets, inform us about the chemical history of the Milky Way, and enable the study of the tail end of the initial mass function. Unfortunately, their physical characteristics are poorly constrained and models struggle to predict their observational properties. As such it is not currently possible to accurately determine the metallicity for field ultracool dwarfs. This can be remedied by studying wide binaries that contain an FGK or early M dwarf primary with an ultracool dwarf companion. Since both stars formed the same molecular cloud, we can use the metallically and age of the primary as a proxy for that of the ultracool dwarf. We've already used this technique to develop methods to measure the metallicities dwarfs as late as M9. We propose to obtain a homogenous set of NIR spectra of L dwarf companions in such benchmark wide binary systems, including a sample of newly discovered binaries from Pan-STARRS. We will combine this with existing data on the primary stars to develop spectroscopic methods to measure the metallicity of L dwarfs.


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