据加州大学伯克利分校2017年6月14日提供的消息, 美国加州大学伯克利分校的理论物理学家和哈佛大学史密森天体物理天文台的射电天文学家合作研究的一项新分析得出结论：所有的恒星形成都是成双成对的。太阳在45亿年前形成时有双胞胎吗? 虽然并非是同卵双胞胎，但是几乎可以肯定的确有孪生体存在。在宇宙中，像太阳一样的每一颗其它恒星都是如此。
许多恒星有同伴, 包括离我们最近的邻居, 半人马座阿尔法星在内, 它是一个三联体系统。天文学家们一直在寻找一种解释。双胞胎和三胞胎星系是以何种方式形成的呢? 一个恒星会捕获另一个恒星吗? 双星有时会分裂和变成为单一的恒星吗? 天文学家甚至一直在寻找太阳的伴星，有一颗被称为“涅墨西斯（Nemesis）的恒星，因为是它将一颗小行星推入到地球轨道，并与地球相撞导致了恐龙的灭绝。
但是，这种情况从未被人们发现。新断言是基于对一种巨大分子云的射电普查，在珀尔修斯星座中巨大分子云充满了最近形成的恒星, 而且只有在所有的类日恒星与生俱来就有一个同伴的条件下，一个数学模型可以解释珀尔修斯观测结果。加州大学伯克利分校的天文学家、也是此项研究的合作者史蒂文•斯塔尔（Steven Stahler）说:“我们说, 是的, 很久以前就有涅墨西斯（Nemesis）存在。
”更多信息请注意浏览原文：New evidence that all stars are born in pairs Sarah I. Sadavoy, Steven W. Stahler. Embedded Binaries and Their Dense Cores. 3 MNRAS 000, 1–16 (2017) , Preprint 2 May 2017, arxiv.org/abs/1705.00049 https://arxiv.org/pdf/1705.00049.pdf ABSTRACT We explore the relationship between young, embedded binaries and their parent cores,using observations within the Perseus Molecular Cloud. We combine recently publishedVLA observations of young stars with core properties obtained from SCUBA-2 observationsat 850 μm. Most embedded binary systems are found toward the centres oftheir parent cores, although several systems have components closer to the core edge.Wide binaries, defined as those systems with physical separations greater than 500au, show a tendency to be aligned with the long axes of their parent cores, whereastight binaries show no preferred orientation. We test a number of simple, evolutionarymodels to account for the observed populations of Class 0 and I sources, both singleand binary. In the model that best explains the observations, all stars form initiallyas wide binaries. These binaries either break up into separate stars or else shrink intotighter orbits. Under the assumption that both stars remain embedded following binarybreakup, we find a total star formation rate of 168 Myr−1. Alternatively, one starmay be ejected from the dense core due to binary breakup. This latter assumptionresults in a star formation rate of 247 Myr−1. Both production rates are in satisfactoryagreement with current estimates from other studies of Perseus. Future observationsshould be able to distinguish between these two possibilities. If our model continuesto provide a good fit to other star-forming regions, then the mass fraction of densecores that becomes stars is double what is currently believed. Key words: stars: formation – stars: binaries – ISM: clouds – ISM: dust, extinction 赵克勤老师指出：集对分析把“事物或概念都是成对地存在”看作是自然界的一个基本原理，称其为“成对原理”，全文发表在《Exploration of Nature》1998年第4期，也可参见《集对分析与奇妙的联系数2—人为什么生2只眼睛？
》http://blog.sciencenet.cn/blog-329317-838442.html 和其他文献，在集对分析的一些专著中对“成对原理”也有介绍，成对原理是集对分析得以提出和发展所依据的一个基本原理。转载本文请联系原作者获取授权，同时请注明本文来自诸平科学网博客。链接地址：http://blog.sciencenet.cn/blog-212210-1060857.html