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

宇宙中密度最大的物质包含在中子星中，中子星的质量相当于我们的太阳，大小相当于超新星爆炸后留下的一座城市。这种物质的性质仍然是一个谜，可能会揭示自然界的基本相互作用。一些尖端的天文天文台，加上最新的致密物质实验室实验，正在收集关于这种最奇异的材料的数据。我们最好的模型预测，恒星的外层，大约半英里厚，是固体(地壳)，而恒星下面的大部分是液体。在过去的十年里，人们花费了巨大的努力来测量这颗恒星的整体性质。然而，类似的努力还没有致力于了解恒星地壳的性质，尽管它影响了中子星随着时间的推移改变其温度、自转和磁场的方式，并产生了星震等令人兴奋的现象。PI将通过对地壳进行类似于为研究核心而开发的最先进的技术来解决这种不平衡问题。PI将检查中子星与生俱来的两个壳层的材料性质，以及来自伴星的物质落到中子星表面后的中子星最终的物质性质。PI将指导来自代表性不足群体的学生，并为他们提供开展研究和发展广泛相关技能的经验。在过去的十年里，核天体物理学通过对大量系统生成的中子星状态方程进行统计分析，集中精力从中子星的质量和半径测量中提取中子星状态方程。这在一定程度上是对数据质量显著提高的反应，因为出现了一些尖端天文台和实验，包括激光干涉引力波天文台(LIGO)、美国国家航空航天局(NASA)的中子星内部成分探测器(NICER)在天文学方面，以及铅(铅)半径实验(PREX)和新完成的稀有同位素束设施(FRIB)在核实验方面。寻找整个状态方程只是研究恒星内部性质的一部分。许多观察到的现象都是中子星具有约一公里厚的固体外壳的直接结果。中子星的冷却，脉冲星毛刺等旋转异常，持续的引力波，磁场演化和星震，都可以承载中子星地壳物理的特征。这个项目将使地壳受到与恒星状态方程相同的统计审查，开发大型地壳模型，并应用天体物理和核数据来第一次获得具有良好特征的不确定性对地壳材料性质的约束，并确定当中子星从伴星吸积物质时这些性质是如何变化的。该项目推进了未来NSF投资的十大想法之一的“宇宙之窗：多信使天体物理时代”的目标。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.