论文标题
低质量恒星周围半径谷的特性：核心驱动质量损失机制的预测
Properties of the radius valley around low mass stars: Predictions from the core-powered mass-loss mechanism
论文作者
论文摘要
近年来，分析小行星大小分布的双峰性，即“半径谷”，使我们对行星形成过程的洞察力有了前所未有的见解。在这里，我们探索了低质量恒星的半径谷的性质，假设核心驱动的质量损失是塑造小型系外行星种群的主要过程。我们表明，行星大小轨道时期空间中半径谷的斜坡并不随着出色的质量而变化，并且负斜坡为$ \ text {d log} r_p/\ r_p/\ text {d log} p \ simeq -0.11 $，即使是最小的0.1 $ m_ \ m_ \ m_ \ odot $ oc od od od od od od od od od od od od od od od od od od odot od od od od od od od od od od odot od od od odot od od od od od odot od od od od o odot。此外，我们发现行星尺寸巨大质量空间中半径谷的斜率是$ \ text {d log} r_p/\ text {d log} m_ \ ast \ ast \ simeq（3ζ-2）/36 $，其中$ζ$由$ l____________________________________________________________________________________________________________________________________________的因为$ζ$是$ \ gtrsim $ 2，并且随着恒星质量的增加而增加，所以我们预测Radius Valley在fgkm矮人的星球尺寸 - 恒星质量空间中具有正斜率。然而，由于与恒星质量的$ζ$变化，该斜率降低了（较高）质量恒星的幅度（增加）。虽然大约1.0 $ m_ \ odot $ start slope是$ \ text {d log} r_p/\ text {d log} m_ \ ast \ sim 0.37 $，但它低至$ \ sim 0.13 $ 0.1 $ m_ \ m_ \ odot $ stars。此外，我们发现半径山谷较窄，而在下部质量恒星周围较少空。最后，我们表明，对于下质量恒星而言，对核心驱动的质量损失的半径谷的预测越来越不同。
In recent years, analyzing the bimodality in the size distribution of small planets, i.e., the `radius valley', has given us unprecedented insight into the planet formation process. Here we explore the properties of the radius valley for low mass stars, assuming that the core-powered mass-loss is the dominant process shaping the small exoplanet population. We show that the slope of radius valley in the planet size-orbital period space, to first-order, does not vary with stellar mass and has a negative slope of $\text{d log}R_p/\text{d log}P \simeq -0.11$ even for stars as small as 0.1 $M_\odot$, as observed in latest studies. Furthermore, we find that the slope of the radius valley in the planet size-stellar mass space is $\text{d log}R_p/\text{d log}M_\ast \simeq (3 ζ- 2)/36$ where $ζ$ is given by the stellar mass-luminosity relation $L_\ast \propto M_\ast^ζ$. Because $ζ$ is $\gtrsim$ 2 and increases with stellar mass, we predict that the radius valley has a positive slope in the planet size-stellar mass space across FGKM dwarfs. This slope, however, decreases (increases) in magnitude towards lower (higher) mass stars, due to the variation of $ζ$ with stellar mass. While around 1.0 $M_\odot$ stars the slope is $\text{d log}R_p/\text{d log}M_\ast \sim 0.37$, it is as low as $\sim 0.13$ around 0.1 $M_\odot$ stars. In addition, we find that the radius valley is narrower and less empty around lower mass stars. Finally, we show that predictions for the radius valley for core-powered mass-loss and photoevaporation become increasingly distinct for lower mass stars.
