Multiple mean motion resonances in the HR 8799 planetary system
Multiple mean motion resonances in the HR 8799 planetary system
复制标题
HR 8799 行星系统中的多个平均运动共振
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
C. Migaszewski
中科院分区：
文献类型：
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作者：
K. Goździewski;C. Migaszewski
HR 8799是一颗附近的恒星，拥有至少4 ~10颗类木质量的行星，它们的宽轨道最高可达~70au，是通过直接的高对比度红外成像探测到的。据报道，大的伴星和碎片盘的内部为~10au，外部为~100au，表明过去存在大质量的原行星盘。由于有限的天文测量数据覆盖了微小的轨道弧，HR 8799系统的动态状态尚未完全确定。我们建立了一个新的HR 8799系统的轨道模型，假设行星在形成后在更宽的轨道上快速迁移。我们发现，HR 8799行星可能参与双拉普拉斯共振，1e:2d:4c:8b MMR。准圆形行星轨道与恒星赤道共面，与天平面倾斜约25度。这个最合适的轨道配置与天体测量、碎片盘模型和冷却模型的质量估计相匹配。在恒星的年龄~160Myr范围内，多重MMR是稳定的，至少维持1gyr，除非存在对n体动力学的显著扰动。我们预测了在~9.7au或~7.5au轨道上假设的第五颗最内层行星HR 8799f的四种构型，将MMR链分别扩展到三重拉普拉斯共振1f:2e:4d:8c:16b MMR或1f:3e:6d:12c:24b MMR。我们的发现可能为该系统的形成及其早期历史建立强有力的边界条件。
HR 8799 is a nearby star hosting at least four ~10 Jovian mass planets in wide orbits up to ~70au, detected through the direct, high-contrast infrared imaging. Large companions and debris disks reported interior to ~10au, and exterior to ~100au indicate massive protoplanetary disc in the past. The dynamical state of the HR 8799 system is not yet fully resolved, due to limited astrometric data covering tiny orbital arcs. We construct a new, orbital model of the HR 8799 system, assuming rapid migration of the planets after their formation in wider orbits. We found that the HR 8799 planets are likely involved in double Laplace resonance, 1e:2d:4c:8b MMR. Quasi-circular planetary orbits are coplanar with the stellar equator and inclined by ~25 degrees to the sky plane. This best-fit orbital configuration matches astrometry, debris disk models, and mass estimates from cooling models. The multiple MMR is stable for the age of the star ~160Myr, for at least 1 Gyr unless significant perturbations to the N-body dynamics are present. We predict four configurations with the fifth hypothetical innermost planet HR 8799f in ~9.7au, or ~7.5au orbit, extending the MMR chain to triple Laplace resonance 1f:2e:4d:8c:16b MMR or to the 1f:3e:6d:12c:24b MMR, respectively. Our findings may establish strong boundary conditions for the system formation and its early history.