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arXiv 2511.04091astro-ph.EP
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年轻超级木星系统中各向同性自转倾角的早期证据

Early evidence for isotropic planetary obliquities in young super-Jupiter systems

University of Toronto(多伦多大学);University of Toronto Mississauga(多伦多大学密西沙加分校);University of Toronto Scarborough(多伦多大学士嘉堡分校);University of Illinois at Urbana-Champaign(伊利诺伊大学厄巴纳-香槟分校);CU Boulder(科罗拉多大学博尔德分校)

Michael Poon, Marta L. Bryan, Hanno Rein, Jiayin Dong, Joshua S. Speagle, Dang Pham

AI总结:

研究通过分层贝叶斯框架分析年轻超级木星系统的自转倾角分布,发现各向同性倾角的证据支持湍流碎片化理论。

摘要:

本十年内首次测量了太阳系外行星自转倾角,表征了系外行星自转轴相对于轨道轴的取向。这些测量是通过结合投影旋转速度、行星自转周期和视差轨道,对直接成像的超级木星进行的。这种方法约束了自转轴和轨道倾角相对于视线的方向,允许对单个系统进行自转倾角测量,并提供了关于其形成的新见解。为测试这些超级木星是像放大版的行星还是缩小版的恒星形成,我们开发了一个分层贝叶斯框架来推断其群体水平的自转倾角分布。使用单参数Fisher分布,我们比较了两种模型:行星样形成场景(κ=5)预测中等对齐,与棕矮星样形成场景(κ=0)预测各向同性自转倾角。基于四个年轻超级木星系统的样本,我们发现早期证据支持各向同性情况,贝叶斯因子为15,与湍流碎片化一致。

英文摘要:

This decade has seen the first measurements of extrasolar planetary obliquities, characterizing how an exoplanet's spin axis is oriented relative to its orbital axis. These measurements are enabled by combining projected rotational velocities, planetary rotation periods, and astrometric orbits for directly-imaged super-Jupiters. This approach constrains both the spin axis and orbital inclination relative to the line of sight, allowing obliquity measurements for individual systems and offering new insights into their formation. To test whether these super-Jupiters form more like scaled-up planets or scaled-down stars, we develop a hierarchical Bayesian framework to infer their population-level obliquity distribution. Using a single-parameter Fisher distribution, we compare two models: a planet-like formation scenario ($κ=5$) predicting moderate alignment, versus a brown dwarf-like formation scenario ($κ=0$) predicting isotropic obliquities. Based on a sample of four young super-Jupiter systems, we find early evidence favoring the isotropic case with a Bayes factor of 15, consistent with turbulent fragmentation.

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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