发表机构
Ludwig-Maximilians-Universität München; Max-Planck-Institut für extraterrestrische Physik; European Southern Observatory (ESO)（慕尼黑大学; 马克斯·普朗克地外物理研究所; 欧洲南方天文台）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
研究次土星伴星结构，汇编86个系统数据构建探测概率面，用泊松 - 二项式框架计算出现率。发现不同区域伴星结构差异显著，支持高偏心率迁移和安静盘迁移或原位形成这两个迁移通道。
AI 中文摘要
近距次土星（半径为4 - 8.5倍地球半径）在海王星沙漠中数量稀少，在P = 3.2 - 5.7天附近的狭窄过密区域（海王星脊）聚集，在更长周期时稀疏分布于人口较适中的稀树草原区域。我们检验次土星是否具有系统不同的伴星结构，如沙漠和海王星脊行星通过高偏心率迁移到达，而稀树草原行星安静迁移的预测。我们汇编了86个有凌星和径向速度数据的系统，构建完整性图并将其组合成伴星探测概率面。用泊松 - 二项式框架计算不同伴星类型的伴星出现率。不同区域伴星结构差异显著。稀树草原次土星中69.9_{-7.7}^{+6.9}%有近距伴星（P < 200天），而沙漠和海王星脊次土星只有10.5_{-5.3}^{+7.8}%。此外，稀树草原次土星常处于多行星系统，64.4_{-9.8}^{+8.9}%有多个伴星行星，沙漠和海王星脊中只有14.9_{-9.1}^{+13.7}%。在两个群体中，现存近距伴星几乎都是小质量的（M < 20倍木星质量）。沙漠和海王星脊次土星处于动态清空系统，其近距伴星率与热木星匹配，而稀树草原次土星处于类似暖木星的紧凑多行星系统。这种平行支持了在单一群体中运行的两个迁移通道：高偏心率迁移将行星送到沙漠和海王星脊，安静的盘迁移或原位形成填充稀树草原。
英文摘要
Close-in sub-Saturns (4.0 - 8.5 R$_\oplus$) are depleted in the Neptunian desert, accumulate in a narrow overdensity near P = 3.2 - 5.7 d (the Neptunian ridge), and thin out into the more moderately populated savanna at longer periods. We test whether sub-Saturns have systematically different companion architectures, as predicted if desert and ridge planets arrived through high-eccentricity migration while savanna planets migrated quiescently. We compile 86 systems with both transit and RV data, construct completeness maps and combine them into detection probability surfaces for companions. The combined completeness maps are used to calculate companion occurrence rates across different companion types with a joint Poisson occurrence model. Companion architectures differ significantly across the landscape. $91.1_{-4.3}^{+3.2}\%$ of savanna sub-Saturns have nearby companions (P < 200 d) compared to only $36_{-14}^{+16}\%$ of desert and ridge sub-Saturns. This contrast is driven almost entirely by small ($M_\mathrm{c} < 20\,\mathrm{M}_\oplus$) companions, which accompany $88.2_{-5.5}^{+4.2}\%$ of savanna but only $29_{-14}^{+17}\%$ of desert and ridge sub-Saturns, while medium-mass and giant companions within 200\,d are rare ($\lesssim 13\%$) everywhere. Savanna sub-Saturns moreover typically reside in compact multi-planet systems. These contrasts are robust to crosscuts in sub-Saturn radius, bulk density, eccentricity, and host-star properties. Desert and ridge sub-Saturns reside in dynamically emptied systems whose nearby companion rates match those of hot Jupiters, while savanna sub-Saturns inhabit compact multi-planet systems resembling those of warm Jupiters. This parallel supports two migration channels operating within a single population: HEM delivering planets to the desert and ridge, and quiescent disk migration or in-situ formation populating the savanna.
Comments28 pages, 13 figures, accepted for publication in A&A
