A Bayesian periodogram finds evidence for three planets in HD 11964

A Bayesian multiplanet Kepler periodogram has been developed for the analysis of precision radial velocity data. The periodogram employs a parallel tempering Markov chain Monte Carlo algorithm. The HD 11964 data have been re‐analysed using 1, 2, 3 and 4 planet models. Assuming that all the models are equally probable a priori, the three planet model is found to be ≥600 times more probable than the next most probable model which is a two planet model. The most probable model exhibits three periods of 38.02+0.06−0.05, 360+4−4 and 1924+44−43 d, and eccentricities of 0.22+0.11−0.22, 0.63+0.34−0.17 and 0.05+0.03−0.05, respectively. Assuming the three signals (each one consistent with a Keplerian orbit) are caused by planets, the corresponding limits on planetary mass (M sin i) and semimajor axis are respectively. The small difference (1.3σ) between the 360‐d period and one year suggests that it might be worth investigating the barycentric correction for the HD 11964 data.