天文学家在遥远的太阳系中发现了一个熟悉的特征

天文学家在遥远的太阳系中发现了一个熟悉的特征

How typical is our Solar System? The question bedevils planetary scientists, but making detections of analogous features in other planetary systems is pretty hard. Yet astronomers have just made one - of a Kuiper belt-like feature around a star 320 light-years away.

我们的太阳系有多典型?这个问题困扰着行星科学家，但要在其他行星系统中探测类似的特征是相当困难的。然而天文学家们刚刚在320光年外的一颗恒星周围形成了柯伊伯带状的一个特征。

It is, they say, the first polarimetric detection of the inner ring circling the star we call HD 141569A. And it's revealing new details about a crucial period of planetary development.

他们说，这是第一次对环绕恒星的内环进行偏振探测，我们称之为HD 141569A，它揭示了行星发展关键时期的新细节。

HD 141569A is actually a pretty interesting and well-studied object. It has two companions in a trinary system, both red dwarfs. But HD 141569A is just 5 million years old, around three times the mass of the Sun, of a blue spectral type burning hot and bright.

HD 141569A实际上是一个非常有趣的研究对象。它有两个同伴，都是红矮星。但HD 141569A只有500万年的历史，大约是太阳质量的三倍，是一种炽热明亮的蓝色光谱类型。

In 1999, a disc was discovered around the young star, with two rings peaking at 220 and 360 astronomical units, respectively. These are the remnants of material that swirled around and accreted into the star as it was forming; over time, bits of material start sticking to each other, accreting into planets.

1999年，在这颗年轻恒星周围发现了一个圆盘，两个环的峰值分别为220和360天文单位。这些是在恒星形成的过程中旋转并吸积到恒星中的物质的残余;随着时间的推移，一些物质开始相互粘着，吸积到行星中。

In HD 141569A's disc, a gap between the two rings suggested that a planet was forming, gravitationally hoovering up all the material in its orbit.

在HD 141569A的圆盘中，两个环之间的间隙表明一颗行星正在形成，在引力作用下吸走了其轨道上的所有物质。

Here in the Solar System, we also have remnants of the Sun's accretion disc from its formation 4.6 billion years ago. We call it the Kuiper belt, and it's a puffy disc of icy debris out beyond the orbit of Neptune. Pluto, at an average distance of 39.5 astronomical units, is in the Kuiper belt.

在太阳系中，我们也有46亿年前太阳吸积盘形成的残余。我们称之为柯伊伯带，它是海王星轨道外一个膨胀的冰碎片盘。冥王星位于柯伊伯带，平均距离为39.5个天文单位。

Towards the end of this planetary accretion process, what is left is known as a debris disc, and it can extend hundreds of astronomical units across. The disc around HD 141569A is a hybrid - it's in transition between a protoplanetary disc and a debris disc.

在这个行星吸积过程接近尾声时，剩下的被称为碎片盘，它可以延伸数百个天文单位。HD141569A周围的圆盘是一个混合体，它在原行星圆盘和碎片圆盘之间过渡。

Hybrid discs are fascinating to planetary scientists, since they can tell us about how gas giants form, and how growing planetesimals interact with the gas and dust in the disc.

混合圆盘对行星科学家很有吸引力，因为它们可以告诉我们气态巨行星是如何形成的，以及成长中的星体是如何与圆盘中的气体和尘埃相互作用的。

Now, by studying scattered and twisted electromagnetic radiation from the region around the star, astronomers led by Juan Sebastian Bruzzone of The University of Western Ontario in Canada have imaged a similar ring around HD 141569A, peaking at a distance of 44 astronomical units from the star.

现在，加拿大安大略大学的胡安·塞巴斯蒂安·布鲁佐内(Juan Sebastian Bruzzone)领导的天文学家通过研究恒星周围区域散射和扭曲的电磁辐射，在HD 141569A附近成像出一个类似的环，在距恒星44个天文单位的距离处达到峰值。

And they have found not just evidence of planetary formation, but hints that there's another ring structure in the disc closer to the star.

他们不仅发现了行星形成的证据，而且还发现了在离恒星较近的圆盘中有另一个环结构的迹象。

Specifically, they found a spiral arm - a feature found in a few other protoplanetary discs, including the two outer rings of HD 141569A, and taken to be the evidence of a forming planet. Based on the features of the spiral arm, the researchers inferred the planet would be around Jupiter's mass or slightly smaller.

具体地说，他们发现了一个螺旋臂，这是在其他一些原行星盘中发现的特征，包括HD 141569A的两个外环，被认为是行星形成的证据。根据旋臂的特征，研究人员推断这颗行星可能在木星的质量附近或稍小一些。

They also compared their observed emission to models to find the best fit for the type of dust that could have produced it. But, even with the best-fit models, there was emission that couldn't be accounted for.

他们还将观测到的排放量与模型进行了比较，以找到最适合可能产生这种排放的粉尘类型的排放量。但是，即使是最合适的车型，也有无法解释的排放。

However, when another ring located closer to the star was added to the calculations, this solved the problem. A belt between 5 and 15 astronomical units reproduced the emission beautifully.

然而，当另一个靠近恒星的环被加入到计算中时，这个问题就解决了。一条5到15个天文单位之间的带完美地再现了辐射。

Aside from the fact that it's pretty danged amazing that astronomers can even achieve such a detection, this is the sort of finely detailed study that can tell us how planets are born.

除了天文学家甚至可以实现这样的探测，这是一个相当惊人的悬而未决的事实之外，这是一种非常详细的研究，可以告诉我们行星是如何诞生的。

In turn, that can tell us more about our own Solar System - and knowing how normal or unusual it is can help us figure out how the heck we got here at all.

反过来，这可以告诉我们更多关于我们自己的太阳系的信息——知道它有多正常或不寻常可以帮助我们搞清楚我们到底是怎么来到这里的。

"Considering resolved imaging data from other high-contrast facilities, the HD 1415169A debris disc shapes up to be made of at least three, and potentially four nested rings, with spiral structures on the three spatially resolved rings," the researchers wrote in their paper.

研究人员在论文中写道：“考虑到来自其他高对比度设施的分辨率成像数据，HD 1415169A碎片盘的形状至少由三个环组成，可能有四个嵌套环，三个空间分辨率环上有螺旋结构。”。

"As such, it is an excellent laboratory for studying dynamically perturbed discs."

“因此，这是一个研究动态扰动盘的优秀实验室。”

The research has been accepted into The Astronomical Journal, and is available on arXiv.

这项研究已被《天文杂志》接受，可在arXiv上查阅。