AAS Meeting #193 - Austin, Texas, January 1999
Session 97. Extra-Solar Planets and the Search for Life
Display, Saturday, January 9, 1999, 9:20am-4:00pm, Exhibit Hall 1

## [97.08] A High-Resolution Search for Stellar Companions to Stars with Planets

J. Patience, A. M. Ghez, R. J. White, C. McCabe (UCLA), B. Macintosh (LLNL), M. C. Liu, J. R. Graham (UCB), C. E. Max, D. Gavel, S. Olivier (LLNL), R. Rudy (Aerospace Corp.), R. Puetter (UCSD), K. Matthews (Caltech), A. J. Weinberger (UCLA)

One of the major observational goals of planet formation studies is the characterization of the environments of the extrasolar planetary systems. Given the frequency of stellar companions -- ~ 100 % of T Tauri stars in nearby star-forming regions (c.f. Ghez et al. 1993, Simon et al. 1995) and ~ 60 % of solar neighborhood G-dwarfs (Duquennoy & Mayor 1991) -- secondary stars are an important factor to consider. In particular, companions may either inhibit planetary formation or significantly alter the orbital evolution of these systems. In order to investigate the connection between binarity and planet formation, we have conducted a high resolution stellar companion search of the known extrasolar planetary systems. With a combination of speckle imaging and adaptive optics observations, we have surveyed the separation range spanning 0\farcs05 to 15\farcs0. Among the 9 systems observed, no new close companions were detected, although several wider visual binaries (e.g. 16 Cyg A/B) are known. Our preliminary analysis implies that at separations greater than ~0\farcs75, the AO detection limits, \DeltaK ~ 7 mag, exclude any companion stars down to the hydrogen-burning limit. For closer separations, typical speckle detection limits are \DeltaK ~ 4 mag at 0\farcs1 and \DeltaK ~ 5 mag at 0\farcs4.