離地球只有1000光年的黑洞

天文學家發(fā)現(xiàn)了一個黑洞，它潛伏在離地球只有1000光年的地方

We can't see them, but they're out there - stellar-mass black holes, peppering the galaxy. And they're closing in. Astronomers have just identified the closest black hole to Earth they've spotted yet, at less than a third of the distance of the previous record-holder.

我們看不到它們，但它們在那里-恒星狀的黑洞，給銀河系增添了色彩。他們正在慢慢靠近我們。天文學家剛剛發(fā)現(xiàn)了離地球最近的黑洞，距離上一個記錄保持者不到三分之一。

This nearby black hole has evaded detection so far since it's very small, and very quiet - detecting black holes is that much harder when they aren't actively slurping down matter from their surrounding space, since they neither emit nor reflect any detectable radiation whatsoever.

到目前為止，附近的黑洞非常小，而且非常安靜，因此無法檢測-當黑洞沒有主動從周圍空間吸取物質(zhì)時，檢測黑洞就困難得多，因為它們既不會發(fā)射也不會反射任何可檢測到的輻射。

But the newly discovered object had a tell. It's in a triple star system, with two B-type main sequence stars, visible from Earth with the naked eye, and previously thought to be a binary system, called HR 6819.

但是這個新發(fā)現(xiàn)的黑洞卻有了回音。它是由三顆恒星組成的系統(tǒng)，其中有兩個B型主序列恒星，用肉眼可以從地球上看到，并且以前被認為是雙星系統(tǒng)，稱為HR 6819。

When astronomers took observations of the system as part of a survey on binary stars, they found something awry. The orbits of those two main sequence stars seemed to be tugged askew.

當天文學家對雙星觀測進行系統(tǒng)觀測時，他們發(fā)現(xiàn)有些不對勁。這兩個主要序列恒星的軌道似乎被拉歪了。

Follow-up observations tracking the star using the MPG/ESO 2.2-metre telescope at European Southern Observatory's (ESO) La Silla Observatory in Chile clinched it. One of the stars, with an estimated mass between 5 and 7 times the mass of the Sun, orbits a gravitational centre of the system every 40 days - not the other star, which is much farther out.

在歐洲南方天文臺(ESO)位于智利的拉希拉天文臺(La Silla Observatory)使用MPG/ESO 2.2米望遠鏡跟蹤這顆恒星時鎖定了它。其中一顆恒星的質(zhì)量估計在太陽質(zhì)量的5到7倍之間，每40天繞著系統(tǒng)的一個引力中心運行一周，而另一顆恒星的質(zhì)量則遠得多。

When analysed, these orbits suggested there were not two, but three objects dancing around each other in orbit. Since the third object was invisible, there was one thing it was far more likely to be than anything else.

分析后，表明在軌道上不是兩個而是三個物體在彼此周圍跳舞。由于第三個物體是不可見的，因此有一件事比其他任何事物都更有可能。

"An invisible object with a mass at least four times that of the Sun can only be a black hole," said astronomer Thomas Rivinius of the European Southern Observatory. Therefore, "this system contains the nearest black hole to Earth that we know of."

歐洲南方天文臺的天文學家托馬斯里維紐斯說：“一個質(zhì)量至少是太陽質(zhì)量四倍的隱形物體，只能是黑洞。”。因此，“這個系統(tǒng)包含了我們所知離地球最近的黑洞。”

And it's just over 1,000 light-years away. Previously, the closest known black hole, A 0620-00, was measured at a distance of 3,300 light-years away.

離我們只有1000光年。此前，已知離我們最近的黑洞A 0620-00，距離我們3300光年。