发表机构
University of Oxford（牛津大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过移除膨胀巨行星后拟合断裂幂律，发现经验质量-半径关系中存在独特的土星质量区（54-258地球质量），并更新了巨行星膨胀的辐照阈值。
AI 中文摘要
经验质量-半径关系长期以来被用于系外行星学中研究行星族群，并为仅已知质量或半径之一的天体预测另一参数。行星类别之间的推断转变也可为理论提供经验支持。然而，当额外因素影响行星参数时（如巨行星的半径膨胀），二维拟合的质量-半径关系可能变得复杂。在本工作中，我们通过将断裂幂律拟合到经过清理的PlanetS样本（已移除膨胀巨行星）上，推导出一个经验质量-半径关系。我们发现，当排除膨胀巨行星时，首选模型包含三个断点和四个分段，显示出在$54\pm3~{\rm M_\oplus} <M< 258\pm11~{\rm M_\oplus}$区间内出现一个独特的土星质量区。在该区间内，行星仍在增长，但增长率低于海王星质量区，这与引力自压缩的开始相一致。我们还更新了巨行星膨胀的辐照阈值，$S_{\rm thr}=99~\rm S_\oplus$（$1.3~\rm ergs\\,s^{-1}\\,cm^{-2}$）；低于$S_{\rm thr}$时，90%的巨行星的半径超出量$\Delta \log{R}<2\sigma$。
英文摘要
Empirical mass-radius relations have long been used in exoplanetology to study planet demographics and to predict masses and radii for objects where only one of these is known. Inferred transitions between planet classes can also provide empirical evidence in support of theory. However, mass-radius relations fitted in two-dimensions can be complicated when additional factors influence the planetary parameters, as is the case with the radius inflation of giant planets. In this work, we present an empirical mass-radius relation derived by fitting a broken power-law to a cleaned PlanetS sample from which inflated giants have been removed. We find that when inflated giants are excluded, the preferred model contains three breakpoints and four segments, showing the emergence of a distinct Saturnian regime between $54\pm3~{\rm M_\oplus} <M< 258\pm11~{\rm M_\oplus}$. In this regime, planets are still growing but at a lower rate than the Neptunian regime, consistent with the onset of gravitational self-compression. We also update the irradiation threshold for giant planet inflation, $S_{\rm thr}=99~\rm S_\oplus$ ($1.3~\rm ergs\,s^{-1}\,cm^{-2}$); below $S_{\rm thr}$, 90% of giant planets have a radius excess $Δ\log{R}<2σ$.
Comments7 pages, 5 figures, accepted for publication in MNRAS
Journal refMon Not R Astron Soc (2026)
