ASTROMETRIC MONITORING OF THE HR 8799 PLANETS: ORBIT CONSTRAINTS FROM SELF-CONSISTENT MEASUREMENTS
ASTROMETRIC MONITORING OF THE HR 8799 PLANETS: ORBIT CONSTRAINTS FROM SELF-CONSISTENT MEASUREMENTS
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HR 8799 行星的天体监测：来自自洽测量的轨道约束
DOI：
10.3847/0004-6256/152/2/28
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
B. Zuckerman
中科院分区：
文献类型：
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作者：
Q. Konopacky;C. Marois;B. Macintosh;R. Galicher;R. Galicher;T. Barman;S. Metchev;S. Metchev;B. Zuckerman
我们介绍了我们正在进行的对HR 8799直接成像的行星系统的监测活动中的新的天体测量结果。这些新的数据点是在2009年至2014年期间用W.M.Keck II 10米望远镜上的NIRC2获得的。此外，我们还介绍了2007年和2008年发表的最新天文测量结果。所有数据都使用Sosie算法进行了简化，该算法解释了以前发表的观测结果中存在的系统性偏差。这使我们能够构建完全从NIRC2数据中派生出来的自洽数据集。从这个数据集，我们探测到两颗行星(HR 8799b和e)在>；3σ的加速度。我们还独立评估了这四颗行星中每一颗可能的轨道参数。我们发现行星允许的倾斜度在统计上没有显著差异。在强制共面的同时对天文测量进行拟合，也会使χ2与最佳拟合值的1σ范围内一致，这表明如果存在≲20°的倾斜偏移量，则无法用当前数据检测到它们。我们的轨道拟合也倾向于低偏心率，这与动力学模型的预测一致。我们还发现周期分布在1σ以内，所有行星之间的共振为1：2：4：8。这一分析表明，在适用于高度欠采样轨道的解决方案时，最大限度地减少天体测量系统学的重要性。
We present new astrometric measurements from our ongoing monitoring campaign of the HR 8799 directly imaged planetary system. These new data points were obtained with NIRC2 on the W.M. Keck II 10 m telescope between 2009 and 2014. In addition, we present updated astrometry from previously published observations in 2007 and 2008. All data were reduced using the SOSIE algorithm, which accounts for systematic biases present in previously published observations. This allows us to construct a self-consistent data set derived entirely from NIRC2 data alone. From this data set, we detect acceleration for two of the planets (HR 8799b and e) at >3σ. We also assess possible orbital parameters for each of the four planets independently. We find no statistically significant difference in the allowed inclinations of the planets. Fitting the astrometry while forcing coplanarity also returns χ2 consistent to within 1σ of the best fit values, suggesting that if inclination offsets of ≲20° are present, they are not detectable with current data. Our orbital fits also favor low eccentricities, consistent with predictions from dynamical modeling. We also find period distributions consistent to within 1σ with a 1:2:4:8 resonance between all planets. This analysis demonstrates the importance of minimizing astrometric systematics when fitting for solutions to highly undersampled orbits.