标题： 罗斯比数区域，对流抑制和膨胀热木星中的发电机磁性 显示英文标题

标题： Rossby number regime, convection suppression, and dynamo-generated magnetism in inflated hot Jupiters

摘要： 热木星（HJs）通常被认为在系外行星中拥有最强的由发电机效应产生的磁场，其强度比木星高一个数量级。因此，它们经常被视为最有可能显示磁星-行星相互作用信号和磁驱动的相干射电辐射的系外行星，尽管进行了多种多样的观测活动，但这一现象仍然难以捉摸。在这项工作中，我们通过一维模型研究了热木星内部对流和发电机特性的演化。我们探讨了轨道距离、行星和恒星质量以及热量注入类型的影响。我们采用一维演化模型来获得内部对流结构。具体而言，在证明潮汐同步对于所有热木星都可能有效之后，我们得到了罗斯比数$\mathrm{Ro}$作为行星深度和轨道周期的函数。当热量均匀施加时，几乎所有热木星的对流层仍处于快速旋转器状态，$\mathrm{Ro} \lesssim 0.1$，除了质量最大的行星且轨道距离较大（但仍被潮汐锁定）。我们通过应用已知的快速旋转器的标度定律来恢复膨胀热木星的磁场强度。当强热源主要施加在外部包层和发电机区域之外时，如现实的欧姆模型所预测的那样，发电机区域的对流通常会崩溃。因此，热通量和推导出的表面磁场可能会大大降低至或低于木星值，这与通常的假设相反，从而对相干射电辐射的估计产生负面影响，并可能解释到目前为止未能检测到它的原因。 显示英文摘要

摘要： Hot Jupiters (HJs) are commonly thought to host the strongest dynamo-generated magnetic fields among exoplanets, up to one order of magnitude larger than Jupiter. Thus, they have often been regarded as the most promising exoplanets to display magnetic star-planet interaction signals and magnetically-driven coherent radio emission, which unfortunately remains elusive, despite many diversified observational campaigns. In this work, we investigate the evolution of the internal convection and dynamo properties of HJs via one-dimensional models. We explore the dependency on orbital distance, planetary and stellar masses, and types of heat injection. We employ one-dimensional evolutionary models to obtain internal convective structures. Specifically, we obtain the Rossby number $\mathrm{Ro}$ as a function of planetary depth and orbital period, after showing that tidal synchronization is likely valid for all HJs. When the heat is applied uniformly, the convective layers of almost all HJs remain in the fast rotator regime, $\mathrm{Ro} \lesssim 0.1$, except possibly the most massive planets with large orbital distances (but still tidally locked). We recover magnetic field strengths for inflated HJs by applying well-known scaling laws for fast rotators. When strong heat sources are applied mostly in the outer envelope and outside the dynamo region, as realistic Ohmic models predict, convection in the dynamo region often breaks down. Consequently, the heat flux and the derived surface magnetic fields can be greatly reduced to or below Jovian values, contrary to what is commonly assumed, thus negatively affecting estimates for coherent radio emission, and possibly explaining the failure in detecting it so far.