Excitation of Orbital Eccentricities of Extrasolar Planets by Repeated Resonance Crossings
Excitation of Orbital Eccentricities of Extrasolar Planets by Repeated Resonance Crossings
复制标题
反复共振穿越激发太阳系外行星的轨道偏心率
DOI：
10.1086/338961
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
E. Thommes
中科院分区：
文献类型：
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作者：
Eugene Chiang;Debra A. Fischer;E. Thommes
已知的太阳系外行星的轨道，位于其母恒星的潮汐环化区域之外，通常基本上是偏心的。相比之下，我们太阳系中的行星轨道近似圆形，反映了行星在近乎轴对称的绕日圆盘内形成。我们提出轨道偏心可能是由两个行星在粘性吸积的星周盘上的发散轨道迁移产生的。这种迁移是发散的，因为外行星与内行星的轨道周期之比越来越大。随着周期比的发散，行星穿过一系列的平均运动共振，但没有被捕获，这些共振放大了它们的轨道偏心率，大致与它们的质量成反比。原行星盘中的强粘度梯度提供了一种方法来调和太阳系气态巨行星的圆形轨道和目前已知的太阳系外行星的偏心轨道。
Orbits of known extrasolar planets that are located outside the tidal circularization regions of their parent stars are often substantially eccentric. By contrast, planetary orbits in our solar system are approximately circular, reflecting planet formation within a nearly axisymmetric, circumsolar disk. We propose that orbital eccentricities may be generated by the divergent orbital migration of two planets in a viscously accreting circumstellar disk. The migration is divergent in the sense that the ratio of the orbital period of the outer planet to that of the inner planet grows. As the period ratio diverges, the planets traverse, but are not captured into, a series of mean motion resonances that amplify their orbital eccentricities in rough inverse proportion to their masses. Strong viscosity gradients in protoplanetary disks offer a way to reconcile the circular orbits of solar system gas giants with the eccentric orbits of currently known extrasolar planets.