A HIGH-PRECISION RADIAL-VELOCITY SURVEY FOR OTHER PLANETARY SYSTEMS

The precise measurement of variations in stellar radial velocities pro vides one of several promising methods of surveying a large sample of nearby solar type stars to detect planetary systems in orbit around th em. The McDonald Observatory Planetary Search (MOPS) was started in 19 87 September with the goal of detecting other nearby planetary systems . A stabilized 12 gas absorption cell placed in front of the entrance slit to the McDonald Observatory 2.7 m telescope coude spectrograph se rves as the velocity metric. With this I2 cell we can achieve radial v elocity measurement precision better than 10 m s-1 in an individual me asurement. At this level we can detect a Jupiter-like planet around a solar-type star, and have some hope of detecting Saturn-like planets i n a long-term survey. The detectability of planets is ultimately limit ed by stellar pulsation modes and photospheric motions. Monthly MOPS o bserving runs allow us to obtain at least 5 independent observations p er year of the 33 solar-type (F5-K7) stars on our observing list. We p resent representative results from the first five years of the survey.