Tidal Dissipation and Evolution of Stars Around Massive Black Holes: An Eccentric Path to Tidal Disruption

当一颗恒星经过一个大质量黑洞(MBH)并被潮汐力量撕裂时，就会发生潮汐扰动事件(TDEs)。这些事件产生了发光的、短暂的耀斑，可以从地球上观察到。当恒星经过MBH的潮汐半径内时，大多数“正常”的TDEs就会发生，从而导致恒星的一次性碎裂。然而，恒星有可能被捕获到高度偏心的轨道上，其最近的接近距离大于潮汐半径。这些恒星不会立即被扰乱，但会与MBH发生多次潮汐相遇。康奈尔大学的一个研究小组将研究这种相遇的物理学，包括在恒星中建立的振荡和波，然后使用强大的计算机模型来确定恒星及其围绕MBH的轨道的演化如何受到影响，以及恒星最终是否会被撕裂。研究团队将包括研究生和本科生，并将制作结果的可视化和动画，用于教育和推广计划。研究团队将研究一种新的TDEs机制，涉及一颗具有MBH的恒星的多个中心附近通道，导致一条本质上不同的演化路径，走向潮汐破坏和潜在的独特观测特征。将开展的项目范围从定义明确到探索性的，这项工作有可能导致新的发现。这项研究将加强对恒星与星系中心MBH之间相互作用的理解，并将有助于解释正在进行的和未来对发光瞬变源的观测。

Tidal disruption events (TDEs) occur when a star passes close to a massive black hole (MBH) and is torn apart by tidal forces. These events produce luminous, short-lived flares, which can be observed from Earth. Most "normal" TDEs occur when the star passes within the tidal radius of the MBH, leading to a one-time shredding of the star. However, it is possible that stars are captured into highly eccentric orbits with closest approach distance larger than the tidal radius. These stars will not be immediately disrupted but will undergo multiple tidal encounters with the MBH.  A research team at Cornell University will study the physics of such encounters, including the oscillations and waves set up in the star, and then use powerful computer models to determine how the evolution of the star and its orbit around the MBH are affected and whether the star will ultimately be torn apart.  The research team will include both graduate and undergraduate students and will produce visualizations and animations of the results for use in educational and outreach programs.The research team will study a new regime for TDEs, involving multiple pericenter passages of a star with a MBH, leading to a qualitatively different evolutionary path toward tidal disruption and a potentially distinct observational signature.  The projects that will be undertaken range from well-defined to exploratory and the work has the potential to lead to new discoveries. The research will enhance the understanding of the interaction between stars and MBHs at the centers of galaxies and will help interpret ongoing and future observations of luminous transient sources.