Earlier studies had suggested that a nearby star, Gliese 667C, had three planets, only one of which might support life. But the very presence of multiple planets made their precise number hard to tease out.
Now Guillem Anglada-EscudÃ© of the University of GÃ¶ttingen in Germany and his colleagues have reanalysed the original data and added some new observations. They found evidence for up to seven worlds, including three rocky planets in the star’s habitable zone, where temperatures should suit life.
“Five are very solidly detected by any standard,” says Anglada-EscudÃ©. “This includes all three habitable zone candidates.” Located about 22 light years away, Gliese 667C is itself part of a triple-star system, making this one of the most crowded planetary neighbourhoods yet.