A second planet orbiting 47 Ursae Majoris

Precise Doppler velocity measurements during 13 yr at Lick Observatory reveal the presence of two planets orbiting the star 47 UMa. The previously detected inner planet is confirmed by the newer velocities that yield a revised orbital period P-b = 1089.0 +/- 2.9 days, M sin i = 2.54 M-J, and eccentricity e(b) = 0.061 +/- 0.014. The residuals to that single-Keplerian fit exhibit a periodicity that is consistent with an additional planetary companion. A simultaneous fit for both planets implies that the outer planet has P-c = 2594 +/- 90 days, a = 3.73 AU, 0 < e(c) < 0.2, and M sin i = 0.76 M-J. Its semimajor axis is the largest yet found for an extrasolar planet, and its angular separation from the host star of 0."26 makes it a good target for direct detection and astrometry. Hipparcos astrometry places limits on the masses of these planets at less than similar to10 MJ, and dynamical modeling places limits on both e(c) and the orbital inclinations. The outer planet induces a velocity semiamplitude of K = 11.1 m s(-1) in the star during its 7 yr orbit, similar to the signal induced on the sun by Jupiter.