大多数行星形成模型预言在主恒星一个天文单位（或从地球到太阳的平均距离）以内会有一个“沙漠之星”。
Most planet-formation models predict a “planet desert” within one astronomical unit (or the average distance from the Earth to the sun) of a host star.
一个天文单位是地球与太阳的距离，大约9300万英里(1.5亿公里)。
One astronomical unit is the distance between the Earth and the sun, about 93 million miles (150 million km).
第二个行星带距离它的恒星为20个天文单位，这相当于太阳系中天王星的位置。
The second asteroid belt lies at about 20 astronomical units from the star, or a position comparable to Uranus in our solar system.
外侧那些沿着轨道运行的彗星距离恒星最远90个天文单位，最近35个天文单位；我们太阳系中的柯伊伯带与太阳的距离为30到50个天文单位。
The outer comet ring orbits from 35 to 90 astronomical units from the star; our solar system's analogous Kuiper Belt extends from about 30 to 50 astronomical units from the sun.
较早的红外天文卫星(IRAS)的一次失败搜寻显示，5倍木星质量天体的距离必须大于10,000天文单位。
A failed search of older IRAS data suggests that an object of 5 MJ would need to have a distance greater than 10,000 AU.
内侧行星带距离它的恒星为3个天文单位——或者相当于太阳系中的行星带与太阳的距离。
The inner belt orbits at a distance of about 3 astronomical units from its star — or about the same position as the asteroid belt in our own solar system.
它每4.7天环绕恒星一周，其轨道为一个适度的椭圆，平均距离仅0.04个天文单位(为水星距太阳的十分之一)。
It orbits its star every 4.7 days, in a moderately elliptical orbit at a mean distance of only 0.04 AU (one tenth of Mercury's distance from the sun).
HR 8799e十分接近其围绕的恒星，它们之间的距离为14.5个天文单位AU；一个天文单位是指地球到太阳的平均距离。
It sits fairly close to its star, at 14.5 astronomical units AU; one AU is the average distance between Earth and our Sun.
这个行星的乐园存在于一个被其他外星猎人所忽视的恒星周围，虽然它距离地球只有12天文单位（39光年）。
The planetary menagerie exists around a star overlooked by other exoplanet hunters, although it is just 12 parsecs (39 light years) from Earth.
为了度量天文距离，人们把光在一年中走过的距离当作一个距离单位。
To measure astronomic distances one takes as a unit that distance which light travels in a year.
为了度量天文距离，人们把光在一年中走过的距离当作一个距离单位。
To measure astronomic distances one takes as a unit that distance which light travels in a year.
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