NOAO >   Observing Info >   Approved Programs >   2001A-0038

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Proposal Information for 2001A-0038


PI: Brian D. Mason, U.S. Naval Observatory, bdm@draco.usno.navy.mil
Address: 3450 Massachusetts Avenue, NW, Washington, DC 20392-5420, USA

CoI: William I. Hartkopf, U.S. Naval Observatory
CoI: Todd J. Henry, Georgia State University
CoI: Theodore J. Rafferty, U.S. Naval Observatory
CoI: David R. Soderblom, Space Telescope Science Institute
CoI: Sean E. Urban, U.S. Naval Observatory

Title: A Multiplicity Survey of Nearby G Dwarf Stars

Abstract: We propose to complete a survey of all (N=3589) solar-type (0.5 < B-V < 1.0), nearby (d < 50 pc) stars for duplicity. The first half of this project is expected to be completed in January, 2001 at KPNO and CTIO on the respective 4-m telescopes. While visual speckle interferometry provides data for the closest separations (0\farcs03 < \rho < 2'' on a 4-m telescope), inclusion of data from the USNO CCD Astrograph project will allow us to extend this to 60+'' (corresponding to physical separations of 1.5 to 3000 au at 50 pc for both techniques). While this provides important data about star formation processes for those stars most like the Sun, the information is also relevant to planetary searches due to the hierarchical nature of multiple systems. Further, the survey (which is 16% complete) of stars fitting the above criteria can be divided into two subsets: a younger population with active chromospheric emission and an older, inactive population. Earlier results for a subset of this list (Mason et al.\ 1998) demonstrated a surprising relationship between multiplicity and age which warrants further investigation. In addition to providing a census of these objects, we will investigate whether the multiplicity fraction of solar-type stars evolves after a few hundred million years; the results will have serious implications for the survivability of planetary systems.


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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