Astronomers stunned by six-planet system frozen in time

Astronomers have discovered a highly unusual planetary system around a nearby star. It holds six planets, all bigger than Earth but smaller than Neptune, a variety that is absent in our Solar System but common across the Milky Way. Moreover, all of the planets orbit in rhythmic harmony, which suggests the system has remained undisturbed since its formation billions of years ago. The brightness of the star, its relative proximity to Earth, and its six orbiting oddities could make the system a perfect laboratory for studying the formation of these planets, known as sub-Neptunes. “It’s a delightful system,” says astronomer Carole Haswell of the Open University, who was not involved in the study, published today in Nature . The planets’ orbits are all tighter than Mercury’s. But if further observations find more planets in the star’s habitable zone where liquid water can exist, Haswell says, “then it could become the most interesting star in the galaxy.” Earth is the largest rocky planet in the Solar System, but the fifth largest overall. Number four is icy Neptune, the smallest of the gas giants but still four times Earth’s size and 17 times more massive. The yawning difference was assumed to be a natural consequence of the conditions in which they formed: the icy reaches of the outer Solar System versus the warmer climes near the Sun. But the discovery of planets between those sizes just about everywhere else in the galaxy has forced...
Source: Science of Aging Knowledge Environment - Category: Geriatrics Source Type: research