theatlantic.com – HD 131399Ab isn’t the first planet found to have three suns. But it is the first such planet to be found in a wide-orbit system—​by far the widest known within a multi-star system. This is weird because multi-star systems are usually so unstable that they ejects planets, ​which are subject to competing gravitation force from all those suns.​This particular planet’s unexpected survival is therefore peculiar, and perhaps revealing. It could mean that such systems are more commonly hosts to planets that scientists tend to think, according to a paper published in the journal Science on Thursday.