Four stars near the bright band of the Milky Way have revealed a secret: 银河系亮带附近的4颗恒星揭示了一个重大秘密:
the presence of a hidden dwarf galaxy. 那就是一个隐藏矮星系的存在。
Six years ago astronomers predicted that such a galaxy might be in that region based on observed ripples in the Milky Way's disk. 天文学家们曾在6年前根据银河系盘面观察到的涟漪推断该区域可能存在一个星系。
The galaxy is small, faint, and dominated by invisible dark matter. 他们推断这是个很小且很微弱的星系,而且主要是由不可见的暗物质组成。
That combination obviously makes it very hard to see. 这样特征的星系大大增加了观测难度。
Furthermore, it lies behind a shroud of dust that blocks any visible light from passing through. 此外在它前面还有一层阻隔任何可见光线通过的尘埃。
Now scientists have identified four stars that appear to belong to the galaxy by examining infrared light, which can cut through dust. 而现在科学家们通过检测可穿透尘埃的红外线已经发现了4颗似乎属于这个星系的恒星。
The stars are known as Cepheid variables. 这些恒星就是我们熟知的造父变星。
They pulse brighter and dimmer in a predictable pattern, which allows astronomers to determine how far they are from us—about 300,000 light years. 在一种可预测的模式中,它们一亮一暗的节奏使得天文学家能够确定它们距离我们究竟有多远—约30万光年。
That distance puts them well beyond the main body of the Milky Way and right where an orbiting dwarf galaxy might lie. 这样的距离使它们远于银河系主体,正好位于一个矮星系轨道的所在。
The finding is in the Astrophysical Journal Letters. 这一发现已经在《天体物理学》杂志上发表。
Dwarf galaxies like this one are thought to contain more dark matter than regular matter. 像这样的矮星系含有的暗物质比普通物质要多。
So tracking down such dwarfs could give researchers more clues in the quest to figure out what dark matter is made of. 所以追踪这种矮星系能为研究人员研究暗物质的组成提供更多线索。
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