Massive ($M >30\,$M$_{\odot}$) stars exhibit luminosities that are near the Eddington-limit for electron scattering causing the increase in opacity associated with iron at $T\approx180,000\,$K to trigger supersonic convection in their outer envelopes. Three dimensional radiative hydrodynamics simulations by Jiang and collaborators with the Athena++ computational tool have found order of magnitude density and radiative flux fluctuations in these convective regions, even at optical depths $\gg100$. We show here that radiation can diffuse out of a parcel during the timescale of convection in these optically thick parts of the star, motivating our use of a "pseudo" Mach number to characterize both the fluctuation amplitudes and their correlations. In this first paper, we derive the impact of these fluctuations on the radiative pressure gradient needed to carry a given radiative luminosity. This implementation leads to a remarkable improvement between 1D and 3D radiative pressure gradients, and builds confidence in our path to an eventual 1D implementation of these intrinsically 3D envelopes. However, simply reducing the radiation pressure gradient is not enough to implement a new 1D model. Rather, we must also account for the impact of two other aspects of turbulent convection: the substantial pressure, and the ability to transport an appreciable fraction of the luminosity, which will be addressed in upcoming works. This turbulent convection also arises in other instances where the stellar luminosity approaches the Eddington luminosity. Hence, our effort should apply to other astrophysical situations where an opacity peak arises in a near Eddington limited, radiation pressure dominated plasma.

中文翻译：

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大质量星包络中的对流驱动 3D 湍流。I. 漫射辐射传输的一维实现

大质量（$M >30\,$M$_{\odot}$）恒星的光度接近电子散射的爱丁顿极限，导致与铁相关的不透明度增加 $T\approx180,000\,$K在它们的外层触发超音速对流。姜和合作者使用 Athena++ 计算工具进行的三维辐射流体动力学模拟发现，即使在光学深度 $\gg100$，这些对流区域中也存在数量级密度和辐射通量波动。我们在这里表明，在恒星这些光学厚部分的对流时间尺度期间，辐射可以从一个包裹中扩散出来，这促使我们使用“伪”马赫数来表征波动幅度及其相关性。在这第一篇论文中，我们推导出这些波动对携带给定辐射光度所需的辐射压力梯度的影响。这种实现导致 1D 和 3D 辐射压力梯度之间的显着改进，并建立了我们对这些本质上 3D 包络的最终 1D 实现路径的信心。然而，仅仅降低辐射压力梯度不足以实现新的一维模型。相反，我们还必须考虑湍流对流的其他两个方面的影响：巨大的压力和传输相当一部分光度的能力，这将在即将到来的工作中解决。这种湍流对流也出现在恒星光度接近爱丁顿光度的其他情况下。因此，