【VOA慢速】科学家在极快运行轨道上发现了两颗“野生”恒星

16310 TED英语演讲课

Unlike the sun, about half of the stars in our Milky Way galaxy orbit another star in what is known as a binary system.

与太阳不同的是，我们的银河系中大约有一半的恒星在所谓的双星系统中环绕另一颗恒星运行。

The word "binary" means two.

“binary”这个词的意思是“双”。

Researchers recently described an unusual binary system in the science publication Nature.

研究人员最近在科学出版物《自然》上描述了一个不寻常的双星系统。

The two stars orbit each other every 51 minutes in one of the fastest orbital periods known for a rare kind of binary star.

这两颗恒星每51分钟绕对方公转一次，其轨道周期是一种罕见双星系统中已知最快的轨道周期之一。

The two stars are about 3,000 light years from Earth.

这两颗恒星距离地球约3000光年。

One light year is the distance light travels in a year.

一光年是光在一年中传播的距离。

The system belongs to a kind of binary star known as cataclysmic variable.

该系统属于一种被称为激变变星的双星。

That term describes a star system that can brighten by as much as 10,000 times for short periods.

这个词描述的是一个可以在短时间内变亮1万倍的恒星系统。

The unusual system includes a star similar to our sun orbiting very closely to what is called a white dwarf.

这个不寻常的系统包括一颗类似于我们太阳的恒星，其轨道非常靠近那颗所谓的白矮星。

A white dwarf is the hot and dense center of a burned out star.

白矮星是一颗燃烧殆尽的恒星的炽热而密集的中心。

Over billions of years, the distance between the two stars has decreased so much

数十亿年来，这两颗恒星之间的距离缩短了很多，

that they are now closer than the moon is to Earth.

现在它们之间的距离比月球到地球的距离还要近。

Massachusetts Institute of Technology space scientist Kevin Burdge was lead writer of the study.

麻省理工学院的太空科学家凯文·伯德格是这项研究的主要作者。

He said, "Imagine if the moon zipped across the sky 10 times a night.

他说：“想象一下假如月亮一晚上划过天空10次。

That's the kind of speed we are talking about."

那就是我们正在谈论的那种速度。”

Because of the small distance between them, the white dwarf is taking material from the larger star.

由于它们之间的距离很短，那颗白矮星正从另一颗较大的恒星上吸收物质。

The larger star is about the same temperature as the sun but it is now only the size of Jupiter, the largest planet in our solar system.

这颗较大恒星的温度与太阳大致相同，但它现在只有木星那么大，木星是太阳系中最大的行星。

The white dwarf has a mass equal to 56 percent of our own sun.

那颗白矮星的质量相当于我们太阳质量的56%。

It is extremely dense, however, because it is only 1.5 times the Earth's width.

然而，它的密度极大，因为它的直径只有地球的1.5倍。

Burdge said, "…when stars die of old age they become white dwarfs - but then this remnant began to eat its companion."

伯德格说：“恒星衰老死亡后会变成白矮星，但随后这些残余物开始吞噬其伴星。”

Burdge added that the white dwarf interrupted the normal development of the first star.

伯德格补充称，那颗白矮星阻断了第一颗恒星的正常发展。

He said the stars have been orbiting each other for 8 billion years.

他说这两颗恒星已经围绕彼此运行了80亿年。

The researchers used data from the Palomar Observatory in California and from telescopes in Hawaii and in the Canary Islands.

研究人员使用了来自加州帕洛玛天文台以及夏威夷和加那利群岛的望远镜的数据。

Stars are mostly made up of hydrogen, with smaller amounts of helium and other elements.

恒星主要是由氢和少量的氦及其他元素组成。

In this system, the larger of the two stars has an unusually large amount of helium.

在这个双星系统中，两颗恒星中较大的那颗拥有异常多的氦。

Scientists say it lost hydrogen from its outer layers to the smaller white dwarf.

科学家表示，其外层的氢流失到更小的那颗白矮星上。

At the same time, its hot center continues to make helium from existing hydrogen through the process of nuclear fusion.

与此同时，其炽热的中心继续通过核聚变过程从现有的氢中产生氦。

The binary system periodically brightens by a huge amount

这个双星系统会周期性地变亮，亮度非常大。

partly because the larger star is being pulled out of its normal shape by the white dwarf's gravity.

部分原因是较大的那颗恒星被那颗白矮星的引力拉扯出正常形状。

There are more than a thousand known cataclysmic variables.

已知的激变变星超过一千种。

Only 12 or so have orbital periods below 75 minutes.

只有12种左右的激变变星拥有低于75分钟的轨道周期。

While the binary system's 51 minutes is quick, it is not the record when compared to other kinds of binaries.

虽然这个双星系统的51分钟很快，但与其他类型的双星系统相比，它并没有创造记录。

The fastest known orbital period among binary stars is just five minutes and 21 seconds.

双星系统中已知最快的轨道周期只有5分21秒。

"There is tons of wild stuff going on in space," noted Burdge.

伯德格指出：“太空中有大量的‘野生’星体存在。”

I'm Gregory Stachel.

格里高利·施塔赫尔为您播报。