Super-Earth

Astronomers have found a nearby "super-Earth" exoplanet that may be capable of supporting life as we know it. An international group of astronomers discovered the planet using NASA's Transiting Exoplanet Survey Satellite (TESS) earlier this year in the constellation Hydra, about 31 light-years from Earth, according to a statement by NASA(One light-year is the distance light travels in a year, about 6 trillion miles, or 10 trillion kilometers). The exoplanet, named GJ 357 d, is believed to be around twice the size of Earth and harbor six times Earth's mass. Located in the outer edge of its host star's "habitable zone," scientists believe that this super-Earth could have water on its surface.

"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," Diana Kossakowski, a researcher at the Max Planck Institute for Astronomy in Heidelberg, Germany, and co-author of the recent study, said in the statement.The potentially habitable planet and two neighboring worlds were found orbiting around a dwarf star, around a third the size and mass of our own sun and 40% cooler.

Further observations showed that GJ 357 d orbits its star every 55.7 days at a distance of around a fifth of Earth's distance from the sun, and could have Earth-like conditions, according to a statement from Cornell University.

天文学家发现附近有一颗“超级地球”外星球，据我们所知可能有生命存在。NASA的一份声明称，今年早些时候一个国际天文学家团队利用NASA的凌日系外行星勘测卫星（TESS）在长蛇座发现了这颗星球，距离地球约31光年（1光年就是光传播一年所经过的距离，约6万亿英里，或10万亿千米）。这颗称为GJ 357 d的外星球据认为大约有地球两倍大，质量为地球的六倍。这颗超级地球位于其主恒星“宜居带”的外缘，科学家认为它表面上会有水。

德国海德堡的马克斯-普朗克天文研究所的研究员Diana Kossakowski是最近这项研究的共同作者，在声明中说：“这颗行星是否有稠密的大气层还有待未来研究进行考证，如果有，就可以吸收足够的热量来加热这颗行星，其表面上就会存在液态水。”已发现这颗潜在的宜居星球和两颗临近的行星围绕一颗白矮星运行，这颗白矮星体积和质量约为太阳的三分之一，温度比太阳低40%。

康奈尔大学的一份声明称，进一步的观察显示GJ 357 d围绕恒星的运行周期为55.7天，距离其主恒星的距离约为日地距离的五分之一，条件与地球相似。