Scientists discover mirror of our solar system in 2 exoplanets forming around a star

科学家在围绕恒星形成的两颗系外行星中发现了太阳系的镜像

Astronomers have observed two planets forming around a distant infant star, thus discovering a planetary system that offers us a look at the appearance of the solar system over 4 billion years ago.

天文学家观测到两颗行星正在一颗遥远的年轻恒星周围形成，从而发现了一个行星系统，让我们得以一窥40多亿年前太阳系的模样。

The infant star in question is named WISPIT 2, and it's located around 437 light-years away with an estimated age of around 5.4 million years old. If that makes this star sound anything but an infant, consider that our middle-aged star, the sun, is 4.6 billion years old.

这颗年轻恒星名为 WISPIT 2，距离我们约437光年，估计年龄约为540万年。如果这个年龄听起来一点也不像“婴儿”，那不妨想一想，我们那颗已步入“中年”的恒星——太阳，年龄约为46亿年。

WISPIT 2 is surrounded by a donut-shaped cloud of gas and dust called a protoplanetary disk in which scientists have now detected two planets, designated WISPIT 2b and WISPIT 2c. And excitingly, there are structural hints with WISPIT 2's protoplanetary disk of more forming protoplanets. "WISPIT 2 is the best look into our own past that we have to date," discovery team leader Chloe Lawlor of the University of Galway, Ireland, said in a statement. "These structures suggest that more planets are currently forming, which we will eventually detect."

WISPIT 2 被一个甜甜圈状的气体和尘埃云所环绕，这种结构被称为“原行星盘”。科学家已经在其中探测到两颗行星，分别被命名为 WISPIT 2b 和 WISPIT 2c。更令人兴奋的是，WISPIT 2 的原行星盘中还显现出一些结构迹象，暗示着可能还有更多原行星正在形成。爱尔兰戈尔韦大学的发现团队负责人克洛伊·劳勒在一份声明中表示：“WISPIT 2 是迄今为止我们能够观察到的、最接近太阳系早期形态的实例。这些结构表明，还有更多行星正在形成之中，我们最终将能够探测到它们。”

WISPIT 2 is only the second system in which astronomers have successfully detected two forming planets. The other system, PDS 70, lacks the extended disk and the distinct gaps and bands seen around WISPIT 2. That means that this system offers an unparalleled look at how planetary systems like our own solar system are formed.

WISPIT 2 是目前天文学家成功探测到两颗正在形成行星的第二个行星系统。另一个系统是 PDS 70，但它缺乏 WISPIT 2 周围所观测到的那种延展的盘状结构，以及清晰可见的间隙和带状特征。这意味着，WISPIT 2 为我们提供了一个前所未有的视角，帮助我们了解类似太阳系这样的行星系统是如何形成的。

"WISPIT 2 gives us a critical laboratory not just to observe the formation of a single planet but an entire planetary system," team member Christian Ginski of the University of Galway said in the statement.

爱尔兰戈尔韦大学的团队成员克里斯蒂安·金斯基在声明中表示：“WISPIT 2 为我们提供了一个关键的‘实验室’，不仅可以观测单个行星的形成过程，还能研究整个行星系统的形成。”

WISPIT 2b was the first infant planet discovered around this infant star, detected last year and determined to have a mass around five times that of Jupiter and orbiting its parent star at a distance equivalent to 60 times the distance between Earth and the sun.

WISPIT 2b 是在这颗年轻恒星周围发现的第一颗“婴儿行星”，于去年被探测到，其质量约为木星的五倍，并以相当于地日距离60倍的轨道半径绕其母恒星运行。

Following this discovery, astronomers found hints of an additional object closer to WISPIT 2, confirming this to be a planet using the Very Large Telescope (VLT) and the VLT Interferometer (VLTI). The newly found planet, WISPIT 2c, orbits its parent star at around 15 times the distance between Earth and the sun, meaning it's about four times closer to its star than WISPIT 2b is.

在这一发现之后，天文学家在更靠近 WISPIT 2 的位置发现了另一个天体的迹象，并利用甚大望远镜（VLT）及其干涉仪（VLTI）确认其为一颗行星。这颗新发现的行星被命名为 WISPIT 2c，其绕母恒星运行的距离约为地日距离的15倍，也就是说，它比 WISPIT 2b 更靠近恒星，大约近四倍。

The researchers then captured an image of this forming planet using the VLT's Spectro-Polarimetric High-Contrast Exoplanet Research (SPHERE) instrument, further confirming it is a planet with another VLT instrument, GRAVITY+.

随后，研究人员利用甚大望远镜的“高对比度系外行星光谱偏振探测仪”（SPHERE）对这颗正在形成的行星进行了成像，并借助另一台甚大望远镜仪器 GRAVITY+ 进一步确认其为一颗行星。

"Critically, our study made use of the recent upgrade to GRAVITY+ without which we would not have been able to get such a clear detection of the planet so close to its star," team member Guillaume Bourdarot of the Max Planck Institute for Extraterrestrial Physics in Germany said in the statement.

德国马普地外物理研究所的团队成员纪尧姆·布尔达罗在声明中表示：“关键在于，我们的研究利用了 GRAVITY+ 的最新升级，否则我们不可能如此清晰地探测到这颗距离恒星如此之近的行星。”

Both WISPIT 2b and WISPIT 2c are carving grooves in the protoplanetary disk around their parent star. This is happening because, as they orbit the star, their gravitational influences collect material from the disk to facilitate their growth.

WISPIT 2b 和 WISPIT 2c 都在其母恒星周围的原行星盘中“刻画”出沟槽。这是因为它们在绕恒星运行时，其引力作用会从盘中聚集物质，从而促进自身的成长。

At least one more planet is indicated in the system by a less-pronounced gap —further out from the system's central star than WISPIT 2b sits. The team hopes this third planet will be visible with the Extremely Large Telescope (ELT), currently under construction in the Atacama Desert region of northern Chile.

在这个行星系统中，一个较不明显的间隙暗示着至少还存在一颗行星——其位置比 WISPIT 2b 更远，距离中心恒星更外侧。研究团队希望，借助正在智利北部阿塔卡马沙漠地区建设中的“极大望远镜”（ELT），能够观测到这第三颗行星。

"We suspect there may be a third planet carving out this gap, potentially of Saturn's mass, owing to the gap's being much narrower and shallower," Lawlor said.

劳勒表示：“我们推测，这个间隙可能是由第三颗行星‘开辟’出来的，其质量或许接近土星，因为这个间隙明显更窄、更浅。”

The team's research was published on Tuesday (March 24) in The Astrophysical Journal Letters.

该团队的研究成果已于3月24日（周二）发表在《天体物理学杂志快报》上。