论文标题
为什么热木星可以很大，但不会太大
Why hot Jupiters can be large but not too large
论文作者
论文摘要
潮汐加热通常用于解释热木星的“半径异常”（即大部分热木星的半径超过1.2个木星半径，而行星进化的标准理论无法解释）。在本文中，我们发现潮汐加热引起了另一种现象“失控的通货膨胀”（即，当潮汐加热速率高于其临界值时，行星通胀变得不稳定，并且失控了）。随着足够强的潮汐加热，发光度最初会随着通货膨胀而增加，但是在其峰值上，它随着通货膨胀而降低，因此加热比冷却更强，并且发生失控的通货膨胀。在这种机制中，辐射感染边界（RCB）附近的不透明度大致缩放为温度到第四功率和热量，无法有效地从行星内部辐射，这会导致失控的通货膨胀（类似于沸腾锅上的紧密盖子）。基于这种机制，我们发现热木星的半径不能超过$ 2.2R_J $，这与观察值非常吻合。我们还为热木星的轨道怪异提供了上限。此外，与观察结果相比，我们推断出潮汐加热位于RCB附近。
Tidal heating is often used to interpret "radius anomaly" of hot Jupiters (i.e. radii of a large fraction of hot Jupiters are in excess of 1.2 Jupiter radius which cannot be interpreted by the standard theory of planetary evolution). In this paper we find that tidal heating induces another phenomenon "runaway inflation" (i.e. planet inflation becomes unstable and out of control when tidal heating rate is above its critical value). With sufficiently strong tidal heating, luminosity initially increases with inflation, but across its peak it decreases with inflation such that heating is stronger than cooling and runaway inflation occurs. In this mechanism, the opacity near radiative-convective boundary (RCB) scales approximately as temperature to the fourth power and heat cannot efficiently radiate away from planet interior, which induces runaway inflation (similar to a tight lid on a boiling pot). Based on this mechanism, we find that radii of hot Jupiters cannot exceed $2.2R_J$, which is in good agreement with the observations. We also give an upper limit for orbital eccentricity of hot Jupiters. Moreover, by comparison to the observations we infer that tidal heating locates near RCB.
