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Session 70 - Searching for Other Planetary Systems.
Display session, Wednesday, January 17
North Banquet Hall, Convention Center
We have obtained over 100 radial velocity measurements of 51 Peg at a precision of 5 \ms, spanning 2 months. We confirm the report of Mayor and Queloz that its velocity varies with a period of 4.22d and low amplitude, indicative of a planetary companion. Our measurements yield the following orbital elements, at the time of writing (1995 Oct.30): P=4.21\pm.02d, K=51.0\pm1.5 \ms, e=0.02\pm0.02 . The curve is sinusoidal within the errors, implying a circular orbit for the planet. Assuming solar mass for the 51 Peg, the planet has minimum mass: M\sin i=0.41 \mjup. The sinusoidal velocities are superimposed on a linear increase in velocity, dv/dt = 0.7 \ms per day, indicating the presence of a second companion having mass greater than 10 \mjup and period greater than \sim1 yr. This second companion may be self-luminous and thus detectable with direct IR imaging.
