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I.J. Kaplan, D.W. Koerner (University of Pennsylvania), T.J. Henry (Georgia State University)
Existing parallax surveys routinely measure changes in apparent stellar positions to within 2 mas by means of CCD imaging against background stars. A dedicated survey using similar techniques could thus expect to detect perturbations due to the gravitational influence of a companion in a regime of importance to our understanding of the substellar companion mass function. This technique could uncover Jupiter-mass (MJ) companions orbiting at 5 AU from late M Dwarfs 8 pc away, or 13-MJ companions (deuterium-burning mass limit) 5 AU from late K dwarfs at a distance of 20 pc. In contrast, previous companion searches with photographic plates did not reliably detect reflex motions of less than 30 mas and produced no conclusive evidence for a single substellar companion. Technological advances in ground-based interferometry promise order-of-magnitude improvements but are not well-suited to large-scale surveys of relatively faint stars. Space-based surveys will do better, but are limited to mission lifetimes that preclude measurement of companions with orbital periods greater than a few years. A survey with small telescopes in each hemisphere can economically probe the substellar companion population in a statistically significant sample for a time period that is not accessible to currently planned space missions. We explore the limits of such a search by calculating detection efficiencies for a variety of observing strategies.
The author(s) of this abstract have provided an email address for comments about the abstract: ijk@brahe.physics.upenn.edu