Neutron Stars as Probes for the Structure of Dense Nuclear Matter

中子星作为致密核物质结构的探测器，加州圣地亚哥州立大学弗里多林·韦伯中子星包含宇宙中最致密的物质之一(装满这种物质的顶针质量为10亿吨)，再加上观测天文学的前所未有的进步，使此类恒星成为进行广泛迷人物理研究的极佳天体物理实验室。其中包括在电子和中子极其丰富的环境中探索核过程，以及在这类物体的核心形成新的物质状态，比如夸克和胶子的等离子体，这是最强大的陆地粒子对撞机正在寻找的。这项由美国国家科学基金会资助的研究项目旨在从观测到的中子星数据中探索这样的过程。它分为两个主要的活动。第一个活动涉及X射线中子星从伴星那里吸积物质。这样的中子星通常每秒会聚集数百万吨的物质，这些物质以光速的很大一部分撞击恒星表面。这导致了恒星表面的热核反应，其灰烬逐渐向内引力，导致恒星外壳发生重大变化(例如核聚变反应)。这项活动的主要目标是探索这些热核反应对吸积中子星的热演化的影响。第二项活动涉及我们对中子星超高密度核心中实现的基本物理的理解，在中子星中，中子和质子可能被分解成它们的夸克成分，创造出一种新的物质状态，称为夸克物质。如果中子星的核心中存在夸克物质，那么它将是一种颜色超导体，其凝聚图案非常复杂。理论上，中子星实际上可能是夸克星，也就是完全由夸克物质组成的物体。在这项活动的框架内，将对潜在的天体物理信号进行研究，以表明“中子星”中存在夸克物质。这些研究活动对于获得杰斐逊实验室、相对论重离子对撞机(RHIC)的天体物理探测器投资的全部物理焦点以及为稀有同位素加速器(RIA)推荐的新投资至关重要。参与该项目的研究人员和学生将开发关于恒星如何工作的多媒体讲座，并将它们呈现给圣地亚哥地区的中学生和教师。

Neutron Stars as Probes for the Structure of Dense Nuclear MatterFridolin Weber, San Diego State University, San Diego, CaliforniaNeutron stars contain matter in one of the densest forms found in theUniverse (a thimble full of such matter would have a mass of onebillion tons) which, together with the unprecedented progress inobservational astronomy, makes such stars superb astrophysicallaboratories for a broad range of fascinating physical studies. Theseinclude the exploration of nuclear processes in an environmentextremely rich of electrons and neutrons, and the formation of newstates of matter in the cores of such objects, like a plasma of quarksand gluons which is being sought at the most powerful terrestrialparticle colliders. This NSF supported research project aims atexploring such processes from observed neutron star data. It isdivided into two major activities.The first activity deals with X-ray neutron stars accreting matterfrom companions. Such neutron stars accrete typically many millionsof tons of matter per second, which hit the stellar surface at asignificant fraction of the speed of light. This leads tothermonuclear reactions on the stellar surface whose ashes gravitategradually inward, causing significant changes (e.g. nuclear fusionreactions) in the star's crust. The major goal of this activity is toexplore the impact of these thermonuclear reactions on the thermalevolution of accreting neutron stars.The second activity concerns our understanding of the fundamentalphysics realized in the ultra-dense core of neutron stars, whereneutrons and protons might be broken up into their quark constituents,creating a new state of matter known as quark matter. If quark matterexists in the cores of neutron stars, it will be a colorsuperconductor whose condensation pattern is very complex. It has alsobeen theorized that neutron stars could in fact be quark stars,objects made entirely of quark matter. In the framework of thisactivity, research on potential astrophysical signatures signaling theexistence of quark matter in "neutron" stars will be carried out.These research activities are crucial to obtain the full physicspotential of the investments that are made in astrophysical detectors,at Jefferson Lab, the Relativistic Heavy Ion Collider (RHIC), as wellas new investments that are recommended for the Rare IsotopeAccelerator (RIA).The researchers and students involved in this project will developmulti-media lectures on how stars work and present them to middleand high school students and teachers in the San Diego area.