Although thousands of exoplanets have been discovered outside our solar system since the 1990s, astronomers are still hunting for something that remains elusive there: exomoons.

尽管自20世纪90年代以来，在太阳系外已经发现了数千颗系外行星，但天文学家仍在寻找一些在那里仍然难以捉摸的东西：系外卫星。

Over the last year, a few researchers have suggested potential evidence for locating these small moons around exoplanets, but nothing has been confirmed.

在过去的一年里，一些研究人员提出了在系外行星周围定位这些小卫星的潜在证据，但没有任何证据得到证实。

Now, researchers believe they have found possible indications of an exomoon orbiting a giant, scorching exoplanet in the Lepus constellation, 550 light-years from Earth.

如今，研究人员相信他们已经发现了可能的迹象，表明在距离地球550光年的Lepus星座中，有一颗外星系围绕着一颗巨大的、灼热的系外行星运行。
And it's comparable to Mustafar, a small volcanic planet sandwiched between two gas giants where Anakin Skywalker undergoes his dark, painful transition into Darth Vader in "Star Wars: Episode III -- Revenge of the Sith."

这和穆斯塔法很像。穆斯塔法是一颗火山星球，夹在两颗气态巨星之间，阿纳金·天行者在《星球大战：第三集——西斯的复仇》中经历了向达斯·维德的黑暗、痛苦的转变。

It would be a dangerous volcanic world with a molten surface of lava, a place where Jedis go to die, perilously familiar to Anakin Skywalker," said Apurva Oza, study author and postdoctoral fellow at the Physics Institute of the University of Bern.

伯尔尼大学物理研究所的研究作者和博士后阿普尔瓦·奥扎说：“这将是一个危险的火山世界，有着熔岩的熔融表面，绝地武士会为此死去，这对阿纳金·天行者来说是非常熟悉的。”

The WASP 49-b exoplanet system includes a gas giant that completes one orbit around its star every three days. The planet was discovered orbiting the WASP 49 star in 2012 via the transit method, which is when an exoplanet passes in front of its star, causing detectable dips in starlight.

WASP 49-b系外行星系统包括一颗气体巨星，每三天绕其恒星运行一周。2012年，人们通过凌日法发现了这颗围绕WASP 49恒星运行的行星。凌日法是指一颗系外行星从其恒星前方经过，导致恒星光线出现可探测到的倾角。

Astronomers believe they found evidence for a moon due to the presence of sodium gas where they didn't expect to find it. The researchers published their findings this week in The Astrophysical Journal.

天文学家认为，他们发现了月球的证据，是因为在他们没想到会发现它的地方存在钠气体。研究人员本周在《天体物理学杂志》上发表了他们的发现。

To understand why sodium gas is a key indicator, the astronomers looked at Jupiter's volcanic moon Io - the most volcanically active body in our solar system, according to NASA.

为了理解为什么钠气体是一个关键指标，天文学家观察了木星的火山卫星IO——根据美国宇航局的说法，它是太阳系中火山活动最活跃的天体。

Volcanoes on Io belch out sodium gas, which is then pulled around Jupiter in a cloud, according to previous research.

根据先前的研究，IO上的火山喷发出钠气体，然后这些钠气体被云层环绕在木星周围。
When applying the Jupiter and Io model to the Wasp 49-b system, "the sodium is right where it should be," Oza said.

奥扎说，当将木星和IO模型应用于黄蜂49-B星系时，“钠就在它应该在的地方。”

But their discovery implies that the exomoon is actually losing mass through the emission of sodium gas at high altitude.

但他们的发现意味着，外月球实际上是通过在高空释放钠气体而失去质量的。

"Sodium and potassium lines are quantum treasures to us astronomers because they are extremely bright," Oza said.

奥扎说：“钠和钾线对我们天文学家来说是量子宝藏，因为它们非常明亮。”

"The vintage street lamps that light up our streets with yellow haze is akin to the gas we are now detecting in the spectra of a dozen exoplanets.

“用黄色烟雾照亮街道的老式路灯，类似于我们现在在十几颗系外行星光谱中探测到的气体。”

"And a system including a star closely orbited by a giant planet with its own moon can actually exist stably for billions of years.

“包括一颗恒星在内的星系，由一颗拥有自己卫星的巨型行星紧密环绕，实际上可以稳定存在数十亿年。”

"The enormous tidal forces in such a system are the key to everything," Oza said.

“在这样一个星系中，巨大的潮汐力是一切的关键。”奥扎说。

Tides create stability for the moon's orbit, which also help to heat it and keep it volcanically active.The researchers also found other potential star systems where moons could be hiding from our view, but they need to find more clues.

潮汐为月球轨道创造了稳定性，这也有助于加热月球并使其保持火山活动。研究人员还发现了其他可能的恒星星系，那里的卫星可能隐藏在我们的视线之外，但这一切都还需要更多的线索才能了解。