The CORALIE survey for southern extrasolar planets. XIV. HD 142022 b: a long-period planetary companion in a wide binary

We report precise Doppler measurements of HD 142022 obtained during the past six years with the CORALIE echelle spectrograph at La Silla Observatory together with a few additional observations made recently with the HARPS echelle spectrograph. Our radial velocities reveal evidence of a planetary companion with an orbital period P=1928⁺⁵³_-39 days, an eccentricity e=0.53^+0.23_-0.18, and a velocity semiamplitude K=92⁺¹⁰²_-29 m s^-1. The inferred companion minimum mass is M_2 sin{i}=5.1^+2.6_-1.5 {M}_Jup and the semimajor axis a=3.03 ± 0.05 AU. Only one full orbital revolution has been monitored yet, and the periastron passage could not be observed since the star was too low on the horizon. The eccentricity and velocity semiamplitude remain therefore quite uncertain and the orbital solution is preliminary. HD 142022 is a chromospherically inactive K0 dwarf, metal rich relative to the Sun, and is the primary component of a wide binary. HD 142022 b is thus a new "planet in binary" candidate, and its high eccentricity might be due to secular interactions with the distant stellar companion.