Since the mid-1920s, different strands of research used stars as “physics laboratories” for investigating the nature of matter under extreme densities and pressures, impossible to realize on Earth. To trace this process this paper is following the evolution of the concept of a dense core in stars, which was important both for an understanding of stellar evolution and as a testing ground for the fast-evolving field of nuclear physics. In spite of the divide between physicists and astrophysicists, some key actors working in the cross-fertilized soil of overlapping but different scientific cultures formulated models and tentative theories that gradually evolved into more realistic and structured astrophysical objects. These investigations culminated in the first contact with general relativity in 1939, when J. Robert Oppenheimer and his students George Volkoff and Hartland Snyder systematically applied the theory to the dense core of a collapsing neutron star. This pioneering application of Einstein’s theory to an astrophysical compact object can be regarded as a milestone in the path eventually leading to the emergence of relativistic astrophysics in the early 1960s.

中文翻译：

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1940年之前的恒星结构和紧凑物体：走向相对论天体物理学

自1920年代中期以来，不同的研究领域都使用恒星作为“物理实验室”来研究在地球上无法实现的极端密度和压力下的物质性质。为了追踪这一过程，本文遵循恒星中密集核的概念的演变，这对于理解恒星演化以及作为快速发展的核物理领域都具有重要意义。尽管物理学家和天体物理学家之间存在分歧，但在重叠但又不同的科学文化的互肥土壤中工作的一些主要参与者制定了模型和试验性理论，这些模型和试验性理论逐渐演变为更现实和结构化的天体物理学对象。这些研究最终于1939年与广义相对论首次接触，当时J. 罗伯特·奥本海默（Robert Oppenheimer）和他的学生乔治·沃尔科夫（George Volkoff）和哈特兰·斯奈德（Hartland Snyder）有系统地将这一理论应用于正在坍塌的中子星的密集核中。爱因斯坦理论在天体紧凑物体上的开创性应用可以被视为最终导致相对论天体物理学在1960年代初出现的道路上的一个里程碑。