NOAO >   Observing Info >   Approved Programs >   2004A-0044

Small NOAO Logo

Proposal Information for 2004A-0044


PI: I. N. Reid, STScI, inr@stsci.edu
Address: 3700 San Martin Drive, Baltimore, MD 21053, USA

CoI: K. L. Cruz, University of Pennsylvania
CoI: J. Liebert, Univ. of Arizona

Title: Meeting the Cool Neighbours: completing the survey

Abstract: Over the past three years we have carried out the first systematic all-sky survey for nearby ultracool dwarfs, using 2MASS data to search for late-M and L dwarfs within 20 parsecs. 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 new L dwarfs and more than 120 M7 to M9 dwarfs, including 60 within our 20 pc. limit, more than doubling the local sample. Only 150 candidates (10% of the total) remain to be observed, but our incompleteness is highest at faint magnitudes where we expect to find the coolest dwarfs but also sample a wide range of spectral types, with contamination by extragalactic sources. This proposal aims to complete follow-up observations of 47 remaining targets with J<14.5 mag which are accessible from KPNO. As before, 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



NOAO >   Observing Info >   Approved Programs >   2004A-0044

noaoprop-help@noao.edu

Small NOAO Logo