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W. D. Cochran (U. Texas), A. P. Hatzes (TLS Tautenburg, Germany)
The McDonald Observatory Planet Search (MOPS) program began operation in September 1987. Phase I of the survey was conducted on the McDonald Observatory 2.7-m Harlan Smith Telescope coude spectrograph six-foot camera, and used telluric O2 lines as the velocity metric. This method gave us a routine radial velocity precision of 15-20 m/s for stars down to about fifth magnitude, but was limited by long-term systematic errors. Phase II of MOPS started in October 1990, utilizing an I2 gas absorption cell on the same spectrograph as a more stable velocity metric. A transition to MOPS Phase III was made in the summer of 1998, with the installation of the cross-dispersed 2dcoude spectrograph on the 2.7-m Harlan Smith Telescope. This instrument, with the I2 cell, now allows 3 m/s velocity precision to be obtained. We present a summary of the results from Phases I and II. Detections of two extrasolar planets (around 16 Cygni B and epsilon Eridani) from this survey have already been announced. We examine the data on the other 34 stars observed in Phases I and II for any possible signals of orbital motion, and place limits on any planetary companions to them.
This work has been supported by the NSF grant AST-9808980 and by NASA grant NAG5-9227.