Space Scientists Find Surprises Around Quaoar

Space Scientists Find Surprises Around Quaoar

Quaoar is a minor¹ planet orbiting the sun beyond Pluto². It is named after a god of creation in Native American mythology³. And it is creating some surprises for astronomers⁵ as it orbits in the cold outer parts of our solar system.

Researchers said recently that they have found a ring surrounding Quaoar similar to the one around the planet Saturn⁶. 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.

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.

"This is the discovery of a ring located in a place that should not be possible," said Bruno Morgado. He is an astronomer⁴ with the Valongo Observatory⁷ at the Federal University of Rio de Janeiro in Brazil. He is the lead writer of the study published in Nature.

Discovered in 2002, Quaoar is currently defined as a minor planet. Some scientists are proposing to call it a dwarf⁸ planet. But it has not yet been officially given that name by the International Astronomical⁹ Union, the scientific group that names astronomy objects.

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 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. Neptune¹⁰, the most distant planet from the sun, orbits at about 30 times the Earth-to-sun distance.

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.

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.

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 celestial¹¹ 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.

Saturn has the largest ring system in our solar system. The other large gas planets - Jupiter, Uranus¹² 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.

Why is Quaoar's ring outside the Roche limit?

Isabella Pagano is with the Astrophysical Observatory of Catania and one of the study's writers. She said rings could form from debris¹³ when the body was formed, or when something collided with the minor planet or another body.

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

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

Words in This Story

astronomer — n. a scientist who studies objects in space

ring –n. a circular object with nothing in the middle

locate –v. to be in a place

dwarf — adj. something that is smaller than normal

debris — n. what is left after something is destroyed

collide — v. the action of two (or more) objects crashing into each other

hint — n. a suggestion or information that can help answer a question

revise — v. to update something with new information, to correct or improve something

1 minor   

adj.较小(少)的，较次要的；n.辅修学科；vi.辅修

参考例句：

• The young actor was given a minor part in the new play.年轻的男演员在这出新戏里被分派担任一个小角色。
• I gave him a minor share of my wealth.我把小部分财产给了他。

2 Pluto   

n.冥王星

参考例句：

• Pluto is the furthest planet from the sun.冥王星是离太阳最远的行星。
• Pluto has an elliptic orbit.冥王星的轨道是椭圆形的。

3 mythology   

n.神话，神话学，神话集

参考例句：

• In Greek mythology,Zeus was the ruler of Gods and men.在希腊神话中，宙斯是众神和人类的统治者。
• He is the hero of Greek mythology.他是希腊民间传说中的英雄。

4 astronomer   

n.天文学家

参考例句：

• A new star attracted the notice of the astronomer.新发现的一颗星引起了那位天文学家的注意。
• He is reputed to have been a good astronomer.他以一个优秀的天文学者闻名于世。

5 astronomers   

n.天文学者，天文学家( astronomer的名词复数 )

参考例句：

• Astronomers can accurately foretell the date,time,and length of future eclipses. 天文学家能精确地预告未来日食月食的日期、时刻和时长。 来自《简明英汉词典》
• Astronomers used to ask why only Saturn has rings. 天文学家们过去一直感到奇怪，为什么只有土星有光环。 来自《简明英汉词典》

6 Saturn   

n.农神，土星

参考例句：

• Astronomers used to ask why only Saturn has rings.天文学家们过去一直感到奇怪，为什么只有土星有光环。
• These comparisons suggested that Saturn is made of lighter materials.这些比较告诉我们，土星由较轻的物质构成。

7 observatory   

n.天文台，气象台，瞭望台，观测台

参考例句：

• Guy's house was close to the observatory.盖伊的房子离天文台很近。
• Officials from Greenwich Observatory have the clock checked twice a day.格林威治天文台的职员们每天对大钟检查两次。

8 dwarf   

n.矮子，侏儒，矮小的动植物；vt.使…矮小

参考例句：

• The dwarf's long arms were not proportional to his height.那侏儒的长臂与他的身高不成比例。
• The dwarf shrugged his shoulders and shook his head. 矮子耸耸肩膀，摇摇头。

9 astronomical   

adj.天文学的，（数字）极大的

参考例句：

• He was an expert on ancient Chinese astronomical literature.他是研究中国古代天文学文献的专家。
• Houses in the village are selling for astronomical prices.乡村的房价正在飙升。

10 Neptune   

n.海王星

参考例句：

• Neptune is the furthest planet from the sun.海王星是离太阳最远的行星。
• Neptune turned out to be a dynamic,stormy world.海王星原来是个有生气、多风暴的世界。

11 celestial   

adj.天体的；天上的

参考例句：

• The rosy light yet beamed like a celestial dawn.玫瑰色的红光依然象天上的朝霞一样绚丽。
• Gravity governs the motions of celestial bodies.万有引力控制着天体的运动。

12 Uranus   

n.天王星

参考例句：

• Uranus is unusual because it is tilted.天王星非常特殊，因为它是倾斜的。
• Uranus represents sudden change and rebellion.天王星代表突然性的改变和反叛。

13 debris   

n.瓦砾堆，废墟，碎片

参考例句：

• After the bombing there was a lot of debris everywhere.轰炸之后到处瓦砾成堆。
• Bacteria sticks to food debris in the teeth,causing decay.细菌附着在牙缝中的食物残渣上，导致蛀牙。