WoU-MMA: Toward an Understanding of Common Envelope Interactions of Binary Stars

观测天文学的变化正在彻底改变我们对短暂夜空的理解。在光学巡天和探测紧密天体合并双星的引力波方面的重大努力揭示了一个动态的、时变的宇宙。哈佛大学的一个研究小组将开发计算模型，研究常见的包络双星相互作用是如何在紧密合并的双星组装过程中导致天文瞬变的，这最终将产生引力波。在普通的包层阶段，一对恒星中的一颗恒星成长并吞没它的伴星。在这些气体环境中，引力使两颗恒星的核心螺旋地靠得更近。从这种相互作用中产生的双星表现出更紧密的轨道和改变的性质。然而，普通信封阶段的细节仍然不确定。这项工作将推动计算建模工具的发展，以便对在普通包络相互作用期间由质量抛射产生的天文瞬变进行直接的模型到数据的比较。该项目包括通过一项名为“AstroBike”的非正式教育推广计划，将恒星天体物理学带到更广泛的社区。这项工作追求的是双星相互作用的短暂但剧烈的共同包层阶段，其中一颗恒星演变成吞没它的双星同伴。在随后的流体动力相互作用中，双星通过轨道收紧和质量吸积的过程进行了转换。常见的包络过程并不罕见——大约10%的恒星在双星系统中会相互作用。此外，共同包络相被认为是黑洞和中子星紧密双星形成的关键，它们可以在引力辐射、引力波和多信使天体物理学的源群的影响下合并。这项工作将直接比较普通包络相互作用的计算模型与通过生成合成可观测数据检测到的天文瞬变系统。这项工作通过建立模型来解决NSF“宇宙之窗：多信使天体物理学”计划的解释标准，该模型将在揭示导致合并双星源群体的进化过程中最大化多信使观测的解释价值。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Changes in observational astronomy are revolutionizing the way we understand the transient night sky. Major efforts in optical surveys and the detection of gravitational waves from merging binaries of compact objects have revealed a dynamic, time-varying universe. A research team at Harvard University will develop computational models to study how common envelope binary-star interactions lead to astronomical transients in the process of the assembly of compact, merging binaries, which will eventually produce gravitational waves. During the common envelope phase, one star in a pair of stars grows to engulf its companion. Drag forces cause the two stellar cores to spiral closer together in the midst of these gaseous surroundings. Binaries that emerge from this interaction exhibit tightened orbits and transformed properties. The details of the common envelope phase, however, remain uncertain. This work will advance computational modeling tools to allow direct model-to-data comparison for astronomical transients generated by mass ejection during common envelope interactions. The project includes an effort to bring stellar astrophysics to a broader community through an informal-education outreach program called "AstroBike." This work pursues the brief but violent common envelope phase of binary star interaction in which one star evolves to engulf its binary companion. During the ensuing hydrodynamic interaction, the binary is transformed by the processes of orbital tightening and mass accretion. The common envelope process is far from rare -- about 10% of stars are in binary systems that will interact. Furthermore, common envelope phases are believed to be critical in the formation of tight binaries of black holes and neutron stars that can merge under the influence of gravitational radiation, the source population for gravitational wave and multi-messenger astrophysics. The work will make direct comparisons of computational models of common envelope interactions with systems detected as astronomical transients through the generation of synthetic observables. This work addresses the Interpretation criterion of NSF's "Windows on the Universe: Multi-Messenger Astrophysics" program by building models that will maximize the interpretive value of multi-messenger observations in revealing the evolutionary processes that lead to the merging-binary source population.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.