标题： 渐近巨星分支恒星及其风中的不对称性。 一。 从三维RHD模型到合成观测结果 显示英文标题

标题： Asymmetries in asymptotic giant branch stars and their winds. I. From 3D RHD models to synthetic observables

摘要： [摘要] AGB恒星是星际介质金属增丰的重要贡献者。在本文中，我们将来自先进RHD模拟的模型作为辐射转移软件的输入，以创建合成观测数据。主要目标是描述AGB恒星的非球对称性，并模拟其对周围尘埃包层的影响。我们开发了工具，将CO5BOLD中的AGB恒星及其尘埃驱动风模型转换为RADMC-3D使用的格式。通过将其作为“尘埃种类”包含进来，并使用CO5BOLD计算的温度数据，我们保留了恒星的不对称形状。使用Mg2SiO4消光数据和空间依赖的颗粒大小来包含星际尘埃。我们比较了使用RADMC-3D创建的图像和SED与使用球对称恒星创建的类似输出模型的图像和SED。我们的CO5BOLD模型在网格中心上方3.4天文单位处显示出显著且成团的尘埃形成，并且在恒星表面可见由大尺度对流细胞引起的结构。基于VLTI的特性，我们创建了简单的合成观测数据。这样的光学干涉仪应该能够检测到这些尘埃云。我们发现包括不对称恒星模型非常重要，因为它们甚至会影响SED。通量水平上的影响可以与星际尘埃的团块性以及由于恒星表面温度变化导致的角度依赖照明引起的通量最大值波长偏移相关联。这里介绍的方法是生成现实的合成观测数据和测试先进3D RHD模型预测的重要一步。以SED的角度依赖性作为未解析数据时间变化的代理，我们得出结论，AGB恒星中观察到的所有变异性不应都被解释为球对称模型意义上的全局变化。 显示英文摘要

摘要： [Abridged] AGB stars are significant contributors to the metal enrichment of the interstellar medium. In this paper, we adapted models from advanced RHD simulations as input for radiative transfer software to create synthetic observables. A major goal is to describe an AGB star's non-sphericity and to simulate its effects on the surrounding dusty envelope. We developed tools to translate models of an AGB star and its dust-driven wind from simulations with CO5BOLD into the format used by RADMC-3D. We preserved the asymmetric shape of the star by including it as a `dust species' and by using temperature data computed in CO5BOLD. Circumstellar dust is included using Mg2SiO4 opacity data with spatially dependent grain sizes. We compared images and SEDs created with RADMC-3D of a model with similar output made with a spherically symmetric star. Our CO5BOLD model features substantial and clumpy dust formation just above 3.4 au from the grid centre, and large-scale structures due to giant convection cells are visible on the stellar surface. With the properties of VLTI as a basis, we have created simple synthetic observables. Such optical interferometers should be able to detect these dust clouds. We find that it is important to include asymmetric stellar models since they even affect the SEDs. Effects on flux levels can be linked to the clumpiness of the circumstellar dust and the angle-dependent illumination resulting from temperature variations on the stellar surface causes shifts in the wavelengths of the flux maximum. The methods presented here are an important step towards producing realistic synthetic observables and testing predictions of advanced 3D RHD models. Taking the angle-dependence of SEDs as a proxy for temporal variations in unresolved data, we conclude that not all variability observed in AGB stars should be interpreted as global changes in the sense of spherical models.