The HARPS search for southern extra-solar planets - XVI. HD?45364, a pair of planets in a 3:2 mean motion resonance

摘要

Precise radial-velocity measurements with the HARPS spectrograph reveal the presence of two planets orbiting the solar-type star HD45364. The companion masses are and , with semi-major axes of a=0.681AU and 0.897AU, and eccentricities of e=0.168 and 0.097, respectively. A dynamical analysis of the system further shows a 3:2mean motion resonance between the two planets, which prevents close encounters and ensures the stability of the system over 5Gyr. This is the first time that such a resonant configuration has been observed for extra-solar planets, although there is an analogue in our Solar System formed by Neptune and Pluto. This singular planetary system may provide important constraints on planetary formation and migration scenarios.Key words: stars: individual: HD45364 - stars: planetary systems - techniques: radial velocities - methods: observational