第1757期:Space Scientists Find Surprises Around Quaoar

Quaoar is a minor planet orbiting the sun beyond Pluto. It is named after a god of creation in Native American mythology. And it is creating some surprises for astronomers as it orbits in the cold outer parts of our solar system.

Quaoar 是一颗绕太阳运行的小行星，位于冥王星之外。 它以美洲原住民神话中的创世神命名。 当它在我们太阳系寒冷的外围运行时，它给天文学家带来了一些惊喜。

Researchers said recently that they have found a ring surrounding Quaoar similar to the one around the planet Saturn. But the ring around Quaoar differs from the current understanding of where rings can form. It is located much further away from it than current scientific understanding would permit.

研究人员最近表示，他们在 Quaoar 周围发现了一个类似于土星周围的环。 但 Quaoar 周围的环与目前对环形成位置的理解不同。 它的位置比目前的科学理解所允许的要远得多。

The distance of the ring from Quaoar places it in a place where scientists believe particles should come together around a planet to form a moon, rather than a ring.

环与 Quaoar 的距离使它位于科学家认为粒子应该聚集在行星周围形成卫星而不是环的地方。

"This is the discovery of a ring located in a place that should not be possible," said Bruno Morgado. He is an astronomer with the Valongo Observatory at the Federal University of Rio de Janeiro in Brazil. He is the lead writer of the study published in Nature.

Bruno Morgado 说：“这是在一个不应该出现的地方发现了一个戒指。” 他是巴西里约热内卢联邦大学 Valongo 天文台的天文学家。 他是发表在《自然》杂志上的这项研究的主要作者。

Discovered in 2002, Quaoar is currently defined as a minor planet. Some scientists are proposing to call it a dwarf planet. But it has not yet been officially given that name by the International Astronomical Union, the scientific group that names astronomy objects.

Quaoar 于 2002 年被发现，目前被定义为一颗小行星。 一些科学家提议称它为矮行星。 但它尚未被国际天文学联合会正式命名，国际天文学联合会是为天文物体命名的科学团体。

Quaoar is about 1,110 kilometers across, which is about one third the size of Earth's moon. But the minor planet is about half the size of the dwarf planet Pluto. Quaoar has a small moon called Weywot, Quaoar's son in mythology. It has a diameter of 170 kilometers and orbits beyond the ring.

Quaoar 的直径约为 1,110 公里，大约是地球月球大小的三分之一。 但这颗小行星的大小大约是矮行星冥王星的一半。 Quaoar 有一个小月亮，叫做 Weywot，是神话中 Quaoar 的儿子。 它的直径为 170 公里，轨道在环外。

Quaoar is in a distant part of the Solar System called the Kuiper belt, which contains many icy bodies. It orbits about 43 times the distance from the sun to the Earth. Neptune, the most distant planet from the sun, orbits at about 30 times the Earth-to-sun distance.

Quaoar 位于太阳系的遥远部分，称为柯伊伯带，其中包含许多冰体。 它绕太阳运行的距离约为太阳到地球距离的 43 倍。 海王星是距太阳最远的行星，其公转距离约为地日距离的 30 倍。

Quaoar's ring was discovered using the European Space Agency's orbiting CHEOPS telescope. The telescope’s main use is to study planets beyond our solar system.

Quaoar 环是使用欧洲航天局的轨道 CHEOPS 望远镜发现的。 该望远镜的主要用途是研究太阳系以外的行星。

The ring is a disk made of ice-covered particles. It is about 4,100 kilometers away from Quaoar's center. It has a diameter of about 8,200 kilometers.

环是由冰覆盖的颗粒制成的圆盘。 距离Quaoar中心约4100公里。 它的直径约为8200公里。

Unlike any other known rings around bodies in space, Quaoar's ring is outside what is called the Roche limit. That is the distance from any celestial body where it gravitational force would cause an approaching object to be pulled apart. Material orbiting outside the Roche limit would be expected to become a moon.

与太空中围绕物体的任何其他已知环不同，Quaoar 的环位于所谓的罗氏极限之外。 这是与任何天体的距离，它的引力会导致接近的物体被拉开。 在罗希极限之外运行的物质有望成为卫星。

Saturn has the largest ring system in our solar system. The other large gas planets - Jupiter, Uranus and Neptune - all have rings, but not as big. Other non-planetary bodies, Chariklo and Haumea, also have rings. All are inside the Roche limit.

土星拥有我们太阳系中最大的环系统。 其他大型气体行星——木星、天王星和海王星——都有环，但没有那么大。 其他非行星天体 Chariklo 和 Haumea 也有环。 都在罗氏限制范围内。

Why is Quaoar’s ring outside the Roche limit?

为什么 Quaoar 的戒指在罗氏限制之外？

Isabella Pagano is with the Astrophysical Observatory of Catania and one of the study’s writers. She said rings could form from debris when the body was formed, or when something collided with the minor planet or another body.

伊莎贝拉·帕加诺 (Isabella Pagano) 在卡塔尼亚天体物理观测站工作，她是该研究的作者之一。 她说，当天体形成时，或者当某物与小行星或其他天体相撞时，环可能会由碎片形成。

But: “We do not have hints at the moment on how the Quaoar ring formed," Pagano said.

但是：“我们目前没有关于 Quaoar 环是如何形成的线索，”Pagano 说。

She added that the science on how large bodies like moons are created might “need to be revised.”

她补充说，关于像卫星这样的大天体是如何形成的科学可能“需要修改”。