We report individual dynamical masses for the brown dwarfs ε Indi B and C, which have spectral types of T1.5 and T6, respectively, measured from astrometric orbit mapping. Our measurements are based on a joint analysis of astrometric data from the Carnegie Astrometric Planet Search and the Cerro Tololo Inter-American Observatory Parallax Investigation, as well as archival high-resolution imaging, and use a Markov chain Monte Carlo method. We find dynamical masses of 75.0?±?0.82 M Jup for the T1.5 B component and 70.1?±?0.68 M Jup for the T6 C component. These masses are surprisingly high for? such cool objects and challenge our understanding of substellar structure and evolution. We discuss several evolutionary scenarios proposed in the literature and find that while none of them can provide conclusive explanations for the high substellar masses, evolutionary models incorporating lower atmospheric opacities come closer to approximating our results. We discuss the details of our astrometric model, its algorithm implementation, and how we determine parameter values via Markov chain Monte Carlo Bayesian inference.
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机译：我们报告了棕矮星εIndi B和C的个体动力学质量，它们的光谱类型分别为T1.5和T6，这是通过天文轨道测绘测得的。我们的测量是基于对卡内基天文行星搜索和Cerro Tololo美洲天文台视差调查的天文数据的联合分析，以及档案高分辨率成像，并使用马尔可夫链蒙特卡罗方法。我们发现，T1.5 B分量的动态质量为75.0±±0.82 M Jup，T6 C分量的动态质量为70.1±±0.68 M Jup。这些群众高得惊人吗？如此酷的物体，挑战了我们对星际结构和演化的理解。我们讨论了文献中提出的几种进化方案，发现尽管它们都不能为高星下质量提供结论性的解释，但结合了较低大气不透明度的进化模型更接近于我们的结果。我们讨论了我们的天文模型的细节，其算法实现以及如何通过马尔可夫链蒙特卡洛贝叶斯推理确定参数值。
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