Nicolaus Copernicus Astronomical Centre, Warsaw, Poland.
Universidad de Concepción, Departamento de Astronomìa, Concepciòn, Chile.
Nature. 2019 Mar;567(7747):200-203. doi: 10.1038/s41586-019-0999-4. Epub 2019 Mar 13.
In the era of precision cosmology, it is essential to determine the Hubble constant empirically with an accuracy of one per cent or better. At present, the uncertainty on this constant is dominated by the uncertainty in the calibration of the Cepheid period-luminosity relationship (also known as the Leavitt law). The Large Magellanic Cloud has traditionally served as the best galaxy with which to calibrate Cepheid period-luminosity relations, and as a result has become the best anchor point for the cosmic distance scale. Eclipsing binary systems composed of late-type stars offer the most precise and accurate way to measure the distance to the Large Magellanic Cloud. Currently the limit of the precision attainable with this technique is about two per cent, and is set by the precision of the existing calibrations of the surface brightness-colour relation. Here we report a calibration of the surface brightness-colour relation with a precision of 0.8 per cent. We use this calibration to determine a geometrical distance to the Large Magellanic Cloud that is precise to 1 per cent based on 20 eclipsing binary systems. The final distance is 49.59 ± 0.09 (statistical) ± 0.54 (systematic) kiloparsecs.
在精确宇宙学时代，精确到百分之一或更好的精度来确定哈勃常数是至关重要的。目前，这个常数的不确定性主要由造父变星周光关系（也称为勒维特定律）校准的不确定性所主导。大麦哲伦云传统上一直是校准造父变星周光关系的最佳星系，因此成为宇宙距离尺度的最佳基准点。由晚型恒星组成的食双星系统提供了测量大麦哲伦云距离的最精确和最准确的方法。目前，这项技术可达到的精度极限约为 2%，这是由现有的表面亮度-颜色关系校准精度所决定的。在这里，我们报告了一种表面亮度-颜色关系的校准，其精度为 0.8%。我们使用这种校准方法，基于 20 个食双星系统，以 1%的精度确定了大麦哲伦云的几何距离。最终的距离为 49.59 ± 0.09（统计）± 0.54（系统）千秒差距。
