AFFIRM MASS - Accretion Flows and Feedback In Realistic Models of MASsive Star formation

内容：预计大质量星星的形成--特别是在质量上限--会受到辐射力和光电离形式的恒星反馈的影响甚至控制。但是数值模拟仅在非常罕见的情况下覆盖了> 100 M的磁区，并且主要针对原始和现今星星形成情况探索了大质量星星反馈的金属丰度依赖性，而没有对这两种极端情况之间的参数空间进行彻底扫描。为了进行模拟的恒星反馈的制度，最大质量的恒星，我们将利用我们最近开发的数值框架。这个星星形成代码是一个独特的工具，因为它能够同时考虑原恒星外流，辐射力和光电离反馈（沿着恒星演化和尘埃演化）。我们建议在大质量预星系坍缩的多物理场数值模型中研究这些反馈效应及其相互作用对形成吸积盘-流出系统的影响。恒星核心从亚天文单位制度到最具特色的高质量星星形成，即原恒星流出和HII地区。我们将确定的星星形成效率的恒星的质量上限的制度，包括其依赖于metallicity.Based上的分析参数，我们预计从占主导地位的光电离反馈在政权的低金属（早期宇宙）占主导地位的辐射力较高的金属（现今的情况下）。我们将测试这些分析动机的假设，定量确定的反馈效率的制度的质量上限的stars.Résumé：我们将使用拟议的第6年延长研究小组调查辐射力和光电离反馈的制度的质量上限的恒星，并确定其金属依赖。特别关注的是从现在的情况下占主导地位的辐射力政权的过渡到占主导地位的光电离反馈的原始星星形成的情况下。除了这些直接的任务，目前正在进行的项目的后续任务包括比较我们最近的数值模型的磁盘碎片和恒星多重性的观测，将已经部署的磁流体动力学能力的代码合并到我们的恒星反馈框架中，并将已经部署的氢热解离和电离模块合并到我们的恒星反馈框架中。

Context: Massive star formation – especially at the upper mass limit – is expected to be influenced or even controlled by stellar feedback in form of radiation forces and photoionization. But numerical simulations have covered the > 100 M⊙ regime only in very rare cases and the metallicity dependence of massive star feedback has been explored mainly for the primordial and present-day star formation case without a thorough scan of the parameter space in between these two extreme cases.Methods: In order to perform simulations of stellar feedback in the regime of the most massive stars, we will utilize our recently developed numerical framework. This star formation code denotes a unique tool in the sense that it is capable of taking into account protostellar outflows, radiation forces, and photoionization feedback simultaneously (along with stellar evolution and dust evolution).Aims: We propose to study the impact of these feedback effects and their interplay onto the forming accretion disk – outflow system in multi-physics numerical models of the collapse of massive pre-stellar cores from the sub-AU regime up to the most distinctive features of high-mass star formation, namely protostellar outflows and HII regions. We will determine the star formation efficiency of the pre-stellar core collapse in the regime of the upper mass limit of stars including its dependence on metallicity.Based on analytical arguments, we expect a transition from dominating photoionization feedback in the regime of low metallicities (early universe) to dominating radiation forces for higher metallicities (present-day case). We will test these analytically motivated hypotheses by quantitatively determining the feedback efficiencies in the regime of the upper mass limit of stars.Résumé: We will use the proposed 6th year extension of the research group to investigate radiation forces and photoionization feedback in the regime of the upper mass limit of stars and determine their metallicity dependence. Special focus is given on the transition from the regime of dominating radiation forces in the present-day case to the regime of dominating photoionization feedback in the primordial star formation case.Additionally to these straight-forward tasks, follow-up tasks of the currently ongoing projects include comparison of our recent numerical models to observations of disk fragmentation and stellar multiplicity, the merging of the already deployed magneto-hydrodynamics capabilities of the code into our stellar feedback framework, and the merging of the already deployed module for thermal dissociation and ionization of hydrogen into our stellar feedback framework.