Observational Consequences of Hydrodynamic Flows on Hot Jupiters
Observational Consequences of Hydrodynamic Flows on Hot Jupiters
复制标题
热木星上水动力流的观测结果
DOI：
10.1086/513185
复制
发表时间：
2007
期刊：
影响因子：
--
通讯作者：
G. Laughlin
中科院分区：
文献类型：
--
作者：
J. Langton;G. Laughlin
我们使用一个基于网格的浅水模式来模拟凌日热木星HD 209458b的大气动力学。在通常假设行星处于零倾角同步自转的情况下，在反恒星点以东76°处有一个定位良好的冷点，从而达到稳定状态。这代表了与以前文献中使用浅水形式主义的模拟所做的预测不同；我们发现，这种不一致是由我们模型中使用的较短的辐射时间尺度的因子解释的。我们还研究了行星处于卡西尼态2的情况，其中期望倾角为~90°。在这种情况下，达到了周期性的平衡，温度略微领先于太阳的强迫。利用这些温度分布，我们计算了来自该行星的圆盘积分测辐射红外光曲线。尽管两种情况下的温度模式有很大的差异，但两种模型的光曲线惊人地相似。在零倾角的情况下，最小光强是最大光强的66%，最小光强出现在凌日前72°。在大倾角情况下，最小值出现在凌日前54°，强度为最大值的58%。
We use a grid-based shallow water model to simulate the atmospheric dynamics of the transiting hot Jupiter HD 209458b. Under the usual assumption that the planet is in synchronous rotation with zero obliquity, a steady state is reached with a well-localized cold spot centered 76° east of the antistellar point. This represents a departure from predictions made by previous simulations in the literature that used the shallow water formalism; we find that the disagreement is explained by the factor of 30 shorter radiative timescale used in our model. We also examine the case that the planet is in Cassini state 2, in which the expected obliquity is ~90°. Under these circumstances, a periodic equilibrium is reached, with the temperature slightly leading the solar forcing. Using these temperature distributions, we calculate disk-integrated bolometric infrared light curves from the planet. The light curves for the two models are surprisingly similar, despite large differences in temperature patterns in the two cases. In the zero-obliquity case, the intensity at the minimum is 66% of the maximum intensity, with the minimum occurring 72° ahead of transit. In the high-obliquity case, the minimum occurs 54° ahead of transit, with an intensity of 58% of the maximum.