Steps Toward the Cosmic Abundance of 3-Helium

二十多年来，人们已经认识到，轻同位素3He的丰度为宇宙最初几分钟的大爆炸模型提供了一个敏感的理论约束。Drs。Bania和Rood建议继续以前由美国国家科学基金会支持的工作，以确定我们银河系和附近星系中围绕热恒星的发光星际气体云（“H II”和行星状星云）中3He/H的丰度比。研究人员已经大大改进了无线电接收器和简化程序，以便探测更微弱的源，并选择那些附近恒星的核演化过程最小的源。预计这个为期三年的计划将对早期宇宙大爆炸模型施加新的限制。

It has been recognized for over twenty years that the abundance of the light isotope 3He provides a sensitive theoretical constraint on Big Bang models of the first few minutes of the Universe. Drs. Bania and Rood propose to continue work previously supported by the NSF to determine the abundance ratio 3He/H in glowing interstellar gas clouds ("H II" and planetary nebulae) surrounding hot stars in our Galaxy and nearby galaxies. The Investigators have substantially improved radio receivers and reduction procedures in order both to detect fainter sources and to select those in which nuclear evolutionary processes in nearby stars have been minimal. It is expected that new constraints can be placed on early Universe Big Bang models as a result of this three year program.