标题： 红巨星周围的重新膨胀热木星 显示英文标题

标题： Re-inflated Warm Jupiters Around Red Giants

摘要： 自首次发现凌星热木星以来，模型一直在试图解释高度受照气体巨星异常大的半径。 我们现在知道，热木星半径异常的大小与行星的受照水平密切相关，此后已开发出众多模型（如潮汐加热、欧姆耗散和热潮汐）来帮助解释这些膨胀的半径。 然而，总的来说，这些模型可以归为两大类：1）直接通过将部分入射辐射沉积到行星内部来膨胀行星半径的模型；2）简单地减缓行星辐射冷却速度的模型，从而使其保留更多的形成热量，并推迟收缩。 在这里，我们提出了一种新的测试方法，以区分这两类模型。 围绕后主序星以中等轨道周期运行的气态巨行星，在其宿主恒星沿次巨星和红巨星分支移动时，会经历其辐射的巨大增加。 如果热木星的膨胀是通过将辐射沉积到行星深处实现的，那么行星半径应随辐射增强而增大。 这意味着，原本未膨胀的中等轨道周期（>10天）气态巨行星可以在其宿主恒星演化过程中重新膨胀。 在这里，我们探讨可能导致“重新膨胀”气态巨行星形成的条件，并研究如何利用此类行星的存在与否来对热木星膨胀机制的物理特性施加独特的限制。 最后，我们探讨了探测这一潜在的重要未被发现行星群体的可能性。 显示英文摘要

摘要： Since the discovery of the first transiting hot Jupiters, models have sought to explain the anomalously large radii of highly irradiated gas giants. We now know that the size of hot Jupiter radius anomalies scales strongly with a planet's level of irradiation and numerous models like tidal heating, ohmic dissipation, and thermal tides have since been developed to help explain these inflated radii. In general however, these models can be grouped into two broad categories: 1) models that directly inflate planetary radii by depositing a fraction of the incident irradiation into the interior and 2) models that simply slow a planet's radiative cooling allowing it to retain more heat from formation and thereby delay contraction. Here we present a new test to distinguish between these two classes of models. Gas giants orbiting at moderate orbital periods around post main sequence stars will experience enormous increases their irradiation as their host stars move up the sub-giant and red-giant branches. If hot Jupiter inflation works by depositing irradiation into the planet's deep interiors then planetary radii should increase in response to the increased irradiation. This means that otherwise non-inflated gas giants at moderate orbital periods >10 days can re-inflate as their host stars evolve. Here we explore the circumstances that can lead to the creation of these "re-inflated" gas giants and examine how the existence or absence of such planets can be used to place unique constraints of the physics of the hot Jupiter inflation mechanism. Finally, we explore the prospects for detecting this potentially important undiscovered population of planets.