Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA, USA.
Science. 2011 Dec 2;334(6060):1245-9. doi: 10.1126/science.1213581. Epub 2011 Nov 10.
In the current cosmological model, only the three lightest elements were created in the first few minutes after the Big Bang; all other elements were produced later in stars. To date, however, heavy elements have been observed in all astrophysical environments. We report the detection of two gas clouds with no discernible elements heavier than hydrogen. These systems exhibit the lowest heavy-element abundance in the early universe, and thus are potential fuel for the most metal-poor halo stars. The detection of deuterium in one system at the level predicted by primordial nucleosynthesis provides a direct confirmation of the standard cosmological model. The composition of these clouds further implies that the transport of heavy elements from galaxies to their surroundings is highly inhomogeneous.
在当前的宇宙学模型中，只有三种最轻的元素是在大爆炸后的最初几分钟内产生的；所有其他元素都是在恒星中产生的。然而，迄今为止，重元素已经在所有天体物理环境中被观测到。我们报告了两个气体云的探测结果，这些气体云中没有可辨别的重元素超过氢。这些系统在早期宇宙中表现出最低的重元素丰度，因此是最贫金属晕星的潜在燃料。在一个系统中探测到氘的水平与原始核合成预测的水平一致，这直接证实了标准宇宙学模型。这些云的组成进一步表明，重元素从星系到其周围环境的传输是高度不均匀的。
