Monte Carlo NLTE Radiation Transfer in Circumstellar Disks

AST0307686PI Bjorkman对恒星周围环境的新的高分辨率观测开始提供关于发生在恒星包层中的物理过程的大量细节。这些观测戏剧性地表明，轴对称结构和块状结构都是普遍存在的，存在于各种天体物理系统中，例如年轻的恒星物体、高度进化的恒星的流出，以及例如在新星和超新星中看到的爆炸性喷发。然而，为了实现利用这些数据来揭示支配这些现象的潜在物理机制的承诺，必须开发足够的理论技术来研究辐射通过具有复杂几何结构的物质的传输。在这项研究中，将对这些环境中的辐射传输进行二维和三维蒙特卡罗模拟。主要研究的几何结构是围绕年轻恒星物体、高度演化的物体和旋转的恒星风产生的轴对称的盘状结构。更多的研究将研究这些环境中的不对称性，例如热星的块状风和星周盘中的螺旋密度波。这项工作既支持博士后研究人员，也支持研究生，因此直接有助于培养未来的研究人员。除了研究生，首席调查员还经常与本科生和交换生合作，从而与巴西的研究人员进行持续的合作。为了帮助丰富当地社区，就这项研究举办了公开讲座，并为K-12教师举办了教师培训讲习班，以帮助培训教师在课堂上实际使用动手活动。最后，本研究正在开发新的并行计算算法，最终将使其他对多维辐射传输感兴趣的研究人员受益。

AST 0307686PI BjorkmanNew high-resolution observations of circumstellar environments are beginning to provide a wealth of detail about the nature of the physical processes occurring in stellar envelopes. These observations dramatically demonstrate that both axisymmetric and clumpy structures are ubiquitous, occurring in a diverse range of astrophysical systems, such as young stellar objects, outflows from highly evolved stars, and the explosive eruptions seen, for example, in novae, and supernovae. However to fulfill the promise of using these data to uncover the underlying physical mechanisms governing these phenomena, adequate theoretical techniques must be developed for investigating the transfer of radiation through matter with complex geometries. In this research 2- and 3-dimensional Monte Carlo simulations of the radiation transfer in these environments will be carried out. The geometries investigated primarily are the axisymmetric, disk-like structures produced around young stellar objects, highly evolved objects, and rotating stellar winds. Additional studies will investigate asymmetries in these environments, such as the clumpy winds of hot stars and spiral density waves in circumstellar disks.Broader Impact. This work supports both a post-doctoral researcher and a graduate student, and hence directly contributes to the training of future researchers. In addition to graduate students, the principle investigator regularly works with undergraduates and exchange students leading to on-going collaborations with researchers in Brazil. To help enrich the local community, public lectures on this research are given, as well as teacher training workshops to K-12 teachers to help train the teachers in the practical use of hands-on activities for their classroom. Finally, this research is developing new parallel computing algorithms, which ultimately will benefit other researchers interested in multi-dimensional radiation transfer.