NOAO >   Observing Info >   Approved Programs >   2003B-0082

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Proposal Information for 2003B-0082


PI: I. Neill Reid, Space Telescope Science Institute, inr@stsci.edu
Address: 3700 San Martin Drive, Baltimore, MD 21218, USA

CoI: Kelle Cruz, University of Pennsylvania
CoI: Jim Liebert, Unicversity of Arizona

Title: Meeting the cool neighbours: covering the sky

Abstract: Over the past two years we have undertaken the first systematic, large-scale survey for nearby ultracool dwarfs, using 2MASS data covering 50% of the sky to search for late-M and L dwarfs within 20 parsecs of the Sun. Our goal is a definitive determination of the luminosity function for late-M and L dwarfs, and hence a statistically robust derivation of the mass function across the hydrogen-burning limit. So far, we have identified over 90 L dwarfs and more than 120 M7 to M9 dwarfs. However, only 50 ultracool dwarfs fall within out 20- parsec limit. With the release of the full 2MASS database, we propose to double this sample by extending coverage to the full sky. We have refined our search criteria and have identified ~300 new candidates, some of which have already been confirmed as ultracool dwarfs in our semester 2003A observations. We will use intermediate resolution optical spectroscopy to determine accurate distances and luminosities, and to characterise the level of chromospheric activity of these sources.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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