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In Search of Nearby Stars: A Parallax Program at CTIO

Todd Henry (Georgia State University)
Phil Ianna (U. of Virginia)
Rene Mendez (NOAO)
Maria Teresa Ruiz (U. de Chile)
Pat Seitzer (U. of Michigan)

We are carrying out a three-year program at CTIO to determine parallaxes for stars in the solar neighborhood. The program, known as CTIOPI for Cerro Tololo Interamerican Observatory Parallax Investigation, targets faint, missing members of the nearby star sample --- primarily white, red and brown dwarfs. As of March 2000, there are 200 stars on the observing list for the 0.9m and 1.5m at CTIO. The results will allow us to improve the luminosities, colors, and temperatures for these common Galactic constituents, broaden the database used to investigate the luminosity function, mass function, kinematics, and multiplicity of stars in the solar neighborhood, estimate the age of the Galactic disk via the white dwarf luminosity function, and provide targets for upcoming extrasolar planetary searches. For this survey, nearby is defined as being within 25 parsecs, the horizon of NASA's NStars Project, which is a new initiative to provide high quality data for targets that will be observed in future space missions.

Further details about the program can be found under the CTIOPI section at