This is an artist’s representation of a brown dwarf. This class of object is too large to be a planet (and did not form in the same way), but is too small to be a star because it cannot sustain nuclear fusion, since it is less massive than even the smallest stars. A brown dwarf is likely to be marked by wind-driven horizontal bands of thick clouds that may alternate with relatively cloud-free bands, giving the object a striped appearance. Whirling storm systems as big as terrestrial continents, or even small planets, might exist. The name ‘brown dwarf’ is actually a misnomer because the object would typically appear red to the naked eye. It is brightest in infrared light. Many brown dwarfs have binary companions. But as they age, the binary system drifts apart and each dwarf goes its separate way, according to a recent Hubble Space Telescope study. The background stars in this illustration are a science visualisation assembled from the Gaia spacecraft star catalogue. The synthesised stars are accurate in terms of position, brightness, and colour. Because this is not an image of the Milky Way, missing are glowing nebulae and dark dust clouds. [Image description: This artist’s representation shows a brown dwarf, an object more massive than a planet but smaller than a star. The dwarf is a cherry-red sphere. It has horizontal stripes of various shades of red that are cloud bands. In the dark background there are myriad stars that are inside our Milky Way galaxy.]
【新唐人北京时间2024年03月26日讯】美国国家航空航天局（NASA）在最近所进行的调查中发现，有些褐矮星（brown dwarf，或称棕矮星 ）孤零零地在太空中独自生存，没有其它褐矮星相伴。这证明了原本成对的褐矮星可能随着时间的推移而“分手”。
褐矮星是比木星还大的天体，但比质量最小的恒星还小，所以不能被归类为恒星。但就像恒星一样，褐矮星可能成对诞生，与另一颗褐矮星互相环绕轨道运行。
NASA藉由其哈勃太空望远镜（Hubble Space Telescope）所进行的调查发现，当褐矮星的年龄比较大时，它们比较不可能有其它褐矮星相伴。
这意味着由两颗褐矮星组成的双星系统，双方之间的引力非常弱，以致于在邻近恒星的吸引之下，它们在相处几亿年之后，就会分道扬镳。
哈勃太空望远镜可以侦测到彼此距离只有4.8亿公里（相当于太阳与主小行星带之间的距离）的双星，但从事本次调查的天文学家在太阳系邻近地区的一些褐矮星中没有发现有任何伴星。
这项研究的主要报告撰写人、加拿大蒙特娄大学（Université de Montréal）研究人员方塔尼夫（Clémence Fontanive）说：“我们的调查证实，在质量最小、温度最低的单独褐矮星中，有相距甚远的伴星是非常罕见的，即便我们观测到比较年轻的褐矮星双星系统也是如此。这意味着这种系统无法随时间存续下去。”
本次哈勃太空望远镜的发现可以进一步支持褐矮星的诞生方式与恒星相同的理论，也就是经由氢分子的重力塌缩而生成。但不同之处在于，褐矮星没有足够的质量维持氢的核融合（又称核聚变）来产生能量，但恒星就有足够的质量。
方塔尼夫表示，银河系中超过一半的恒星都有伴星，它们是在恒星形成过程中产生的。比较巨大的恒星比较常在双星系统中被发现。
她说，他们的调查所提供的直接证据显示，他们观测到的年轻褐矮星双星系统不太可能存续到年老时，它们可能会分开。这是因为褐矮星非常轻，双星系统中两颗褐矮星之间的引力非常弱，附近的恒星很容易就把两者拆散。
参与这项研究的英国爱丁堡大学（University of Edinburgh）研究人员比勒（Beth Biller）补充说：“大多数恒星都有朋友，无论那是双星系统或系外行星。”
她说，这项调查确实证实，褐矮星的情况并非如此。褐矮星在生命的初期经历一段有同伴的短暂时光之后，大多数都会在馀生中保持“单身”。
方塔尼夫说：“这是到目前为止，成对褐矮星随时间分离的最佳观测证据。如果没有哈勃太空望远镜的敏锐观测能力和灵敏度，我们无法完成这种调查。”
（转自大纪元/责任编辑：叶萍）
![This is an artist’s representation of a brown dwarf. This class of object is too large to be a planet (and did not form in the same way), but is too small to be a star because it cannot sustain nuclear fusion, since it is less massive than even the smallest stars. A brown dwarf is likely to be marked by wind-driven horizontal bands of thick clouds that may alternate with relatively cloud-free bands, giving the object a striped appearance. Whirling storm systems as big as terrestrial continents, or even small planets, might exist. The name ‘brown dwarf’ is actually a misnomer because the object would typically appear red to the naked eye. It is brightest in infrared light. Many brown dwarfs have binary companions. But as they age, the binary system drifts apart and each dwarf goes its separate way, according to a recent Hubble Space Telescope study. The background stars in this illustration are a science visualisation assembled from the Gaia spacecraft star catalogue. The synthesised stars are accurate in terms of position, brightness, and colour. Because this is not an image of the Milky Way, missing are glowing nebulae and dark dust clouds. [Image description: This artist’s representation shows a brown dwarf, an object more massive than a planet but smaller than a star. The dwarf is a cherry-red sphere. It has horizontal stripes of various shades of red that are cloud bands. In the dark background there are myriad stars that are inside our Milky Way galaxy.]](https://i.ntdtv.com/assets/uploads/2024/03/id103865240-heic2405a.jpg)
