RUI: Neutron Star Crusts in Multi-Messenger Astronomy: Probability Distributions of Ground State and Accreted Crusts with Rigorously Quantified Modeling Uncertainty.

宇宙中的致密物质包含在中子星中--中子星的质量与我们的太阳相当，大小相当于超新星爆炸后留下的城市。这种物质的性质仍然是一个谜，可以揭示自然界的基本相互作用。一些尖端的天文观测站，加上实验室对致密物质的最新实验，正在收集这种最奇特物质的数据。我们最好的模型预测，大约半英里厚的星星外层是固体（地壳），而下面的大部分星星是液体。在过去的十年里，人们花费了巨大的努力来测量星星的整体属性。然而，类似的努力尚未致力于了解星星外壳的性质，尽管它对中子星随时间改变其温度，旋转和磁场的方式产生影响，并引起令人兴奋的现象，如星震。PI将通过对地壳进行类似于为研究核心而开发的最先进技术来解决这种不平衡。PI将检查中子星出生时所具有的外壳的材料特性，以及这些中子星在伴星星星的物质福尔斯落在它们的表面后所具有的外壳的材料特性。PI将指导来自代表性不足群体的学生，并为他们提供进行研究和开发各种相关技能的经验。在过去的十年里，核天体物理学界一直致力于通过对大量系统生成的中子星星状态方程（EOS）进行统计分析，从中子星的质量和半径测量中提取EOS。在某种程度上，这是对数据质量显著提高的回应，随着一些尖端观测站和实验的出现，包括激光干涉引力波观测站（LIGO），美国宇航局的中子星星内部成分探测器（NICER），在核实验方面，铅半径实验（PREX）和新完成的稀有同位素束设施（FRIB）。找到整体的状态方程只是研究星星内部性质的一部分。许多观测到的现象都是中子星星有一公里厚的固体外壳的直接结果。中子星的冷却、旋转异常（如脉冲星故障）、持续的引力波、磁场演化和星震都可能带有中子星星地壳物理学的特征。该项目将对地壳进行与星星状态方程相同的统计审查，开发大量地壳模型，并应用天体物理学和核数据，首次获得对地壳物质特性具有明确特征的不确定性的制约因素，并确定当中子星星从伴星吸积物质时这些性质如何变化。该项目推进了““宇宙之窗：多信使天体物理学时代”，NSF未来投资的十大创意之一。该奖项反映了NSF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。

The densest matter in the universe is contained within neutron stars – an object with the mass of our Sun and the size of a city left behind after a supernova explosion. The properties of this matter remain a mystery and could shed light on the fundamental interactions of nature. A number of cutting edge astronomical observatories coupled with the latest in laboratory experiments on dense matter are gathering data on this most exotic of materials. Our best models predict that the outer layer of the star, about half a mile thick, is a solid (the crust), and the bulk of the star beneath is a liquid. Over the last decade, a huge effort been expended measuring the properties of the star overall. However, a similar effort has not yet been devoted to understanding the properties of the crust of the star, despite its impact on the way neutron stars change their temperature, rotation and magnetic field over time, and give rise to exciting phenomena such as starquakes. The PI will address this imbalance by subjecting the crust to similar state-of-the-art techniques as have been developed for studying the core. The PI will examine the material properties of both the crusts the neutron stars are born with, and those neutron stars end up with after matter from a companion star falls onto their surface. The PI will mentor students from underrepresented groups and give them experience conducting research and developing a wide range of associated skills. The last decade has seen the nuclear astrophysics community focus on extracting the neutron star equation-of-state (EOS) from measurements of the masses and radii of neutron stars by performing statistical analyses on large ensembles of systematically generated EOSs. In part this is a response to a marked increase in the quality of the data with the advent of a number of cutting-edge observatories and experiments including the Laser Interferometric Gravitational-wave Observatory (LIGO), NASA’s Neutron star Interior Composition ExploreR (NICER) on the astronomy side, and the Lead (Pb) Radius Experiment (PREX) and the newly completed Facility for Rare Isotope Beams (FRIB) on the nuclear experimental side. Finding the overall EOS is just one strand of research into the interior properties of the star. Many observed phenomena are a direct result of the neutron star having a solid crust about a kilometer thick. The cooling of neutron stars, rotational anomalies such as pulsar glitches, persistent gravitational waves, magnetic field evolution and starquakes could all bear the signatures of the physics of the neutron star crust. This project will subject the crust to the same statistical scrutiny as the EOS of the star, developing large ensembles of crust models and applying astrophysical and nuclear data to obtain, for the first time, constraints with well characterized uncertainty on the material properties of crusts, and determine how those properties change when a neutron star accretes material from a companion.This project advances the objectives of "Windows on the Universe: the Era of Multi-Messenger Astrophysics", one of the 10 Big Ideas for Future NSF Investments.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.