TESS finds potentially habitable super-Earth 31 light-years away
TESS卫星发现在31光年外可能适合居住的超级地球
来源：CNN 翻译：世界播
After completing its first year of observations in the southern sky, NASA"s Transiting Exoplanet Survey Satellite has spotted some intriguing new exoplanets only 31 light-years away from Earth.
美国宇航局的凌日系外行星勘测卫星（TESS）在完成第一年对南方天空的观测后，发现了几颗距离地球仅31光年的迷人新系外行星。
Multiple exoplanets -- planets orbiting stars outside our solar system -- were discovered orbiting an M-dwarf star, called GJ 357 in the Hydra constellation. The star is 40% cooler than our sun and only about a third of the sun"s mass and size. A study describing the three planets was published this week in the journal Astronomy & Astrophysics.
多颗系外行星——围绕太阳系外恒星运行的行星——被发现围绕着一颗M型红矮星运行，这颗红矮星位于长蛇座，被称为GJ357。这颗恒星比我们的太阳冷40%，只有太阳质量和大小的三分之一左右。本周发表在《天文学与天体物理学》杂志上的一项研究介绍了这三颗围绕GJ357运行的行星。
The first exoplanet discovered around the star was GJ 357 b.
在这颗恒星周围发现的第一颗系外行星是GJ357 b。
The exoplanet is 22% larger and 80% more massive than Earth, making it a super-Earth. It"s 11 times closer to its star than Mercury is to our sun and the researchers estimate that it has an average temperature of 490 degrees Fahrenheit. This does not account for any potential warming effects of an atmosphere if it has one. It completes one orbit around the star every 3.9 days.
这颗系外行星比地球大22%，质量比地球大80%，是一个超级地球。它离其恒星的距离是水星离太阳距离的11倍，研究人员估计它的平均温度为490华氏度。这并不能解释是否大气存在任何潜在的变暖效应（如果它有大气层的话）。它每3.9天绕恒星一周。
"We describe GJ 357 b as a "hot Earth,"" said Enric Pallé, study co-author and astrophysicist at the Institute of Astrophysics of the Canary Islands. "Although it cannot host life, it is noteworthy as the third-nearest transiting exoplanet known to date and one of the best rocky planets we have for measuring the composition of any atmosphere it may possess."
“我们将GJ 357 b描述为一个‘热地球’，”研究的合作者、加那利群岛天体物理研究所的天体物理学家恩里克·帕雷说，“尽管它不能承载生命，但值得注意的是，它是迄今为止已知的第三颗离我们最近的凌日系外行星，也是我们发现的最好的石质行星之一，可以用来测量它可能拥有的任何大气成分。”
The researchers also discovered more signals of exoplanets in the system.
研究人员还在星系中发现了更多系外行星的信号。
GJ 357 d, a super-Earth that is 6.1 times the Earth"s mass, is the most intriguing because it orbits the star at a distance where the temperature might be just right to support liquid water on the surface.
超级地球GJ357 d的质量是地球的6.1倍，它是最令人感兴趣的，因为它远远地围绕恒星运行，其表面的温度可能刚好适宜液态水的存在。
"GJ 357 d is located within the outer edge of its star"s habitable zone, where it receives about the same amount of stellar energy from its star as Mars does from the Sun," said Diana Kossakowski, study co-author at at the Max Planck Institute for Astronomy. "If the planet has a dense atmosphere, which will take future studies to determine, it could trap enough heat to warm the planet and allow liquid water on its surface."
“GJ 357 d位于其恒星宜居带的外边缘，在那里，它从恒星接收到的恒星能量与火星从太阳接收到的能量差不多，”马克斯普朗克天文研究所的研究合着者戴安娜·科萨科夫斯基说，“如果这颗行星有稠密的大气层——这将需要未来的研究来确定，它可能会吸收足够的热量使行星变暖，并允许液态水在其表面存在。”
The researchers don"t know if the super-Earth is rocky like our own planet, but it orbits the star every 55.7 days and has a temperature of negative 64 degrees Fahrenheit. An atmosphere could cause it to be warmer.
研究人员尚不知道这颗超级地球是否像我们的星球一样是岩石构成的，不过它每55.7天绕恒星运行一周，温度为零下64华氏度。大气可能使它变暖。
"This is exciting, as this is humanity"s first nearby super-Earth that could harbor life -- uncovered with help from TESS, our small, mighty mission with a huge reach," said Lisa Kaltenegger, study author, associate professor of astronomy and director of Cornell"s Carl Sagan Institute. "With a thick atmosphere, the planet GJ 357 d could maintain liquid water on its surface like Earth and we could pick out signs of life with upcoming telescopes soon to be online."
研究报告的撰写者、天文学副教授、康奈尔大学卡尔·萨根研究所所长莉萨·柯廷安说：“这很令人兴奋，因为这是人类在附近发现的第一个可能孕育生命的超级地球。它是在TESS卫星的帮助下发现的。TESS卫星是我们一个小而强大的任务，覆盖范围很广。由于大气层很厚，这颗GJ357 d行星可以像地球一样维持其表面的液态水，我们可以通过即将上线的望远镜发现生命迹象。”
In the middle of those two planets is GJ 357 c. It"s 3.4 times the mass of Earth and zips around the planet every 9.1 days, reaching a temperature of 260 degrees Fahrenheit.
这两颗行星的中间是GJ 357 c，是地球质量的3.4倍，每9.1天就绕恒星一周，温度达到260华氏度。
"In a way, these planets were hiding in measurements made at numerous observatories over many years," said Rafael Luque, study author and doctoral student at the Canary Islands institute.
“在某种程度上，这些行星隐藏在多年来许多天文台的测量数据中。”该研究的作者、加那利群岛研究所博士生拉斐尔·卢克说。
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