Universidad de Concepción, Departamento de Astronomía, Casilla 160-C, Concepción, Chile.
Nature. 2013 Mar 7;495(7439):76-9. doi: 10.1038/nature11878.
In the era of precision cosmology, it is essential to determine the Hubble constant to an accuracy of three per cent or better. At present, its uncertainty is dominated by the uncertainty in the distance to the Large Magellanic Cloud (LMC), which, being our second-closest galaxy, serves as the best anchor point for the cosmic distance scale. Observations of eclipsing binaries offer a unique opportunity to measure stellar parameters and distances precisely and accurately. The eclipsing-binary method was previously applied to the LMC, but the accuracy of the distance results was lessened by the need to model the bright, early-type systems used in those studies. Here we report determinations of the distances to eight long-period, late-type eclipsing systems in the LMC, composed of cool, giant stars. For these systems, we can accurately measure both the linear and the angular sizes of their components and avoid the most important problems related to the hot, early-type systems. The LMC distance that we derive from these systems (49.97 ± 0.19 (statistical) ± 1.11 (systematic) kiloparsecs) is accurate to 2.2 per cent and provides a firm base for a 3-per-cent determination of the Hubble constant, with prospects for improvement to 2 per cent in the future.
在精确宇宙学时代，将哈勃常数的精度确定到百分之三或更好是至关重要的。目前，其不确定性主要由大麦哲伦云（LMC）距离的不确定性所主导，而 LMC 作为我们第二近的星系，是宇宙距离尺度的最佳基准点。食双星的观测为精确、准确地测量恒星参数和距离提供了独特的机会。食双星方法以前曾应用于 LMC，但由于需要对这些研究中使用的亮、早型系统进行建模，因此距离结果的准确性降低了。在这里，我们报告了对 LMC 中八个长周期、晚型食双星系统的距离的确定，这些系统由冷的巨星组成。对于这些系统，我们可以准确地测量它们的组件的线性和角度大小，并避免与热、早型系统相关的最重要问题。我们从这些系统中得出的 LMC 距离（49.97 ± 0.19（统计）± 1.11（系统）千秒差距）精确到 2.2%，为哈勃常数的 3%确定提供了坚实的基础，并有望在未来提高到 2%。
