Astronomers from the University of Chicago and University of California, Berkeley, announced on May 11, 2016 that their analysis of a four-planet system – discovered several years ago by the Kepler spacecraft – reveals something interesting and rare. The four Neptune-size planets around the star Kepler-223 – all nestled close to the star – are orbiting in a unique resonance that has been locked in for billions of years. For every three orbits of the outermost planet, the second orbits four times, the third six times and the innermost eight times.
Such orbital resonances are not uncommon – our own dwarf planet Pluto orbits the sun twice during the same period that Neptune completes three orbits – but a four-planet resonance is.
[We] are particularly interested in this stellar system because our system’s four giant planets – Jupiter, Saturn, Neptune and Uranus – are thought to have once been in resonant orbits that were disrupted sometime during their 4.5-billion-year history.
The Kepler-223 star system can help us understand how our solar system and other stellar systems discovered in the past few decades formed.
In particular, it could help resolve the question of whether planets stay in the same place they formed, or whether they move closer to or farther from their star over the eons.
Bottom line: The star Kepler-223 has four Neptune-sized planets – close to their star – orbiting in a unique resonance.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.