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arXiv 1909.04059astro-ph.EP
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行星系GJ4276中的动力学相互作用

Dynamical Interactions in the Planetary System GJ4276

Fergus Horrobin, Hanno Rein

摘要:

GJ4276是一颗M4.0的矮星,根据径向速度(RV)观测,推测它是海王星质量的行星。我们重新分析了这个系统的RV数据,并专注于第二个超级地球质量行星的可能性。我们计算的时间尺度为快速共振振动的偏心率为$\sim 2\,000\,\mathrm{days}$。鉴于观测是在$700\,\mathrm{days}$上进行的,我们希望在观测中看到这些振动的影响。我们执行一个完全动态的拟合来测试这个假设。与以前的结果类似,我们确定数据可以由两个行星以2:1的平均运动共振拟合。然而,我们也发现解决方案附近的5:4平均运动共振,不存在时,行星行星相互作用被忽略。利用MEGNO指标,我们分析了系统的稳定性,发现我们的解位于参数空间的稳定区域。我们还发现,虽然出共振的解决方案是可能的,该系统有利于一个配置,这是在一阶平均运动共振。平均运动共振的存在在许多行星形成理论中都有重要的意义。虽然我们并不试图在这项工作中区分一个和两个行星模型,在任何一种情况下,预测的轨道参数是足够有趣的,值得进一步研究。未来的观测应该能够区分下一个$5\,\mathrm{years}$中的不同情景。

英文摘要:

GJ4276 is an M4.0 dwarf star with an inferred Neptune mass planet from radial velocity (RV) observations. We reanalyse the RV data for this system and focus on the possibility of a second, super earth mass, planet. We compute the timescale for fast resonant librations in the eccentricity to be $\sim 2\,000\,\mathrm{days}$. Given that the observations were taken over $700\,\mathrm{days}$, we expect to see the effect of these librations in the observations. We perform a fully dynamical fit to test this hypothesis. Similar to previous results, we determine that the data could be fit by two planets in a 2:1 mean motion resonance. However, we also find solutions near the 5:4 mean motion resonance which are not present when planet-planet interactions are ignored. Using the MEGNO indicator, we analyze the stability of the system and find that our solutions lie in a stable region of parameter space. We also find that though out of resonance solutions are possible, the system favours a configuration which is in a first order mean motion resonance. The existence of mean motion resonances has important implications in many planet formation theories. Although we do not attempt to distinguish between the one and two planet models in this work, in either case, the predicted orbital parameters are interesting enough to merit further study. Future observations should be able to distinguish between the different scenarios within the next $5\,\mathrm{years}$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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