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We know about thousands of planets around other stars in the Milky Way, but most of them are really far away.
我们都知道，银河系其他恒星附近有大概上千颗星星，但其中大多数星星都离我们非常遥远。
That makes them pretty hard to study in enough detail to answer questions like whether or not any of them are habitable.
因此，我们很难仔细地研究这些行星，也就无法解答许多问题，比如，它们是否宜居。
Fortunately, NASA has a satellite on the job, and this week it dropped a shiny new planetary system right in our laps;
幸运的是，美国宇航局（NASA）有一颗卫星会执行与此有关的任务——本周，这颗卫星在与我们重合的地方释放了一个闪闪发亮的小行星系统。
one that's close enough and cooperative enough to carry out those detailed studies.
该系统与我们距离很近，能充分配合我们进行具体的而研究。
In a paper in the journal Nature Astronomy, a team of researchers described three planets around the nearby star TOI-270.
《自然天文学》上发表了一篇论文，该论文的研究团队在此文中描述了恒星TOI-270附近的3颗行星。
That's a small m dwarf star, more commonly referred to as a red dwarf, just 73 light-years from Earth.
这是一颗体型不大的小m矮星，我们一般将它成为红矮星，它距离地球只有73光年的距离。
The planets were found with TESS, the Transiting Exoplanet Survey Satellite, which has been searching for planets since 2018.
凌日系外行星巡天卫星（TESS）发现了这几颗卫星，自2018年以来，TESS就在搜寻行星。
And in that time, it's been logging new discoveries at a steady clip.
那时候，TESS正在稳步记录新发现。
As its name suggests, TESS looks for exoplanets with the transit method, which searches for dips in a star's light as a planet passes in front of it.
凌日系外行星巡天卫星（TESS），顾名思义，就是要用中天法搜寻系外行星，也就是搜选某刻行星通过一颗恒星正面的时候，恒星光的倾角。
It's the same principle that was used by the Kepler Space Telescope, but TESS takes a slightly different approach.
这个理论，开普勒太空望远镜也用过，不过TESS的角度略有不同。
While Kepler stared at the same patch of sky for years on end, TESS looks somewhere new about once a month.
开普勒太空望远镜是连续多年盯着天空中的同一片区域，而TESS则是用大概一个月的时间来观测新的地方。
The shorter viewing window means it can only spot the easy ones:
TESS的取景器更短，这意味着TESS只能观测简单的地方：
close-in planets around bright, nearby stars.
附近明亮恒星附近行星近景。
But those it does find will be among the easiest for scientists to investigate further.
但它找到的那些则是科学家可以进一步研究的最简单的对象。
And the planetary system around TOI-270 should be particularly easy to study because the star itself is unusually tame.
TOI-270附近的行星体系应该尤其容易研究，这是因为恒星本身就特别的好研究。
Most m dwarfs live turbulent lives, frequently experiencing powerful storms and emitting violent solar flares.
大多数m矮星的一生都会发生许多动荡的变化，会频繁经历强力风暴并释放出剧烈的太阳耀斑。
That all leads to ongoing fluctuations in brightness, which is kind of a problem when you're searching for planets using a method that specifically looks for changes in brightness.
这都会导致当前亮度的剧烈波动，这会是个问题，因为如果要通过亮度变化的方法来搜寻行星的话，就会受到影响。
TOI-270 doesn't fit this pattern though, possibly because it's older than many other nearby dwarf stars.
不过，TOI-270并不符合这个模式，这很有可能是因为它的年龄比附近的许多矮恒星都要大。
TESS found three planets orbiting close to the star, creatively named TOI-270 b, c, and d.
TESS发现，该恒星附近有3颗行星环形，我们就姑且称之为TOI-270 b、c、d吧。
“b” is a so-called super-Earth, about 1.2 times the radius of our planet.
TOI-270 b就是所谓的超级地球，其大小是地球半径的近1.2倍。
The others are categorized as sub-Neptunes and are a bit more than two times bigger than Earth, but smaller than Neptune.
还有一些可以归类为次海王星，其大小是地球的两倍多，但还是比海王星要小。
These kinds of planets are especially exciting to astronomers because planets in between Earth and Neptune in size might represent the most common types in the galaxy.
这类行星让天文学家尤为激动，因为地球和海王星大小之间的行星可能代表着银河系里最常规的行星类型。
But neither super-Earths nor sub-Neptunes are found in our own solar system.
不过，在我们自己的太阳系里并未发现超级地球或者超级海王星。
All three of these new worlds orbit TOI-270 with periods of 11 days or less, which means they're probably too close to fall in the star's habitable zone.
新世界里的这3颗行星环绕TOI-270飞行，周期在11天或以内。这意味着，它们很有可能因为离得太近而无法掉落到该恒星的宜居地带。
But that doesn't mean that there can't be any habitable planets here.
但这并不意味着这里没有宜居行星。
Since TESS only observed this system for about 27 days, it could only detect planets with periods of a couple weeks or less.
由于TESS观测该体系的时间大概是27天，所以它只能在几周甚至更少的时间里检测到行星。
That's because ideally, you need to see a planet pass by several times to be certain it's there.
这是因为，理想情况下，需要看到行星通过数次才能确定行星就在那里。
Follow-up observations by other telescopes might reveal additional planets farther from the star.
其他望远镜的后续观测可能会揭示出距离该恒星十分遥远的额外行星。
If there are habitable worlds, TOI-270's quiet nature means life would probably have an easier time getting started.
如果还有什么星体是宜居的话，那么TOI-270安静的性格就意味着生命在一开始萌发的时候，日子过的更容易一些。
And even if there aren't any others, there's still a lot more that astronomers can learn from these three that we've already found.
即便没有其它的了，依然有很多天文学家可以从它们3个身上了解的信息。
These 3 are all in resonance with one another, which means each orbits the star in a length of time that's roughly a whole number multiple of one of its counterparts.
这3颗行星彼此之间有共振，也就是说，每一颗行星都环绕这颗恒星运行一段时间，所以他们彼此环绕次数是有成比例的关系。
The closest makes five orbits in the same time the middle one needs to make three.
距离最近的行星环绕5次轨道的同时，距离第二近的环绕3次轨道。
And that middle one goes around twice for every one orbit made by the outermost planet.
而距离第二近的环绕轨道的次数是距离最远行星环绕的次数的2倍。
This intricate dance is similar to motion in our own solar system.
这种盘根错节的环行方式与太阳系类似。
The three inner moons of Jupiter have a similar relationship, as do Neptune and Pluto.
木星内环轨道的3颗卫星关系类似，就像海王星和冥王星一样。
Such resonances help stabilize the system, but they're also useful to astronomers as a tool for weighing the planets themselves.
这样的共振关系可以让这个系统稳定起来，不过，他们对宇航员来说是有用的工具，可以掂量行星之间的关系。
In systems with multiple planets, the gravitational tug each exerts on the others causes slight wobbles in their orbits.
在有多颗行星的系统中，彼此间的引力作用会让它们运行出现不稳。
And astronomers see these wobbles as slight timing errors between when a planet's transit is expected to start and when it actually does.
天文学家会观测实际开始时间和预测开始时间之间的间隔，视为微弱的误差。
Record enough of these errors and you can figure out how much mass each planet must have to cause the wobbles.
在记录了充分的误差数据后，就能知道每颗行星必须要有多大的质量才能引发不稳定情况。
And because they line up repeatedly, planets in resonance show more variation than those that don't.
由于它们经常会出现在同一条直线上，所以有共振的行星，它们的变化比没有共振的行星更多。
Although TESS didn't collect enough data to make this calculation, the paper's authors believe it should be pretty straightforward for someone else to do.
虽然TESS收集的数据还不够多，不足以做这样的计算，但该文作者认为还是能做的。
They're also looking forward to making observations with NASA's upcoming James Webb Space Telescope,
它们期待用NASA即将上线的詹姆斯·韦伯太空望远镜来做观测。
and these measurements will help reveal the composition of each planet's atmosphere and shed further light on whether they could be at all habitable.
这些测量将助力揭示每颗行星大气层的组成结构，并进一步揭示是否宜居。
All these future opportunities suggest that TOI-270 will continue to be a favorite of scientists for years to come!
这些未来可能出现的机会表明TOI-270在未来数年中依然是天文学家的最爱之一。
