摘要：We report the discovery of a second long-period giant planet orbiting HD 30177, a star previously known to host a massive Jupiter analog (HD 30177b: a = 3.8 ± 0.1 au, m sin i = 9.7 ± 0.5 M Jup). HD 30177c can be regarded as a massive Saturn analog in this system, with a = 9.9 ± 1.0 au and m sin i = 7.6 ± 3.1 M Jup. The formal best-fit solution slightly favors a closer-in planet at a ~ 7 au, but detailed n-body dynamical simulations show that configuration to be unstable. A shallow local minimum of longer period, lower eccentricity solutions was found to be dynamically stable, and hence we adopt the longer period in this work. The proposed ~32 year orbit remains incomplete; further monitoring of this and other stars is necessary to reveal the population of distant gas giant planets with orbital separations a ~ 10 au, analogous to that of Saturn.
