Planets around a nearby star found to all keep time with each other
A rare system of six planets, all kept perfectly in balance, has been found around a star just 100 lightyears away. The star, HD110067, is so near to us that it’s the brightest-known system with four or more planets, making it an ideal candidate for further study.
The system was first uncovered in 2020 by the Transiting Exoplanet Survey Satellite (TESS), which initially found just two planets. A second set of observations hinted there were actually four, but their orbits proved difficult to pin down. Intrigued by the unusual system, a team of astronomers used ESA’s Characterising Exoplanet Satellite (CHEOPS) to study the star, eventually confirming the presence of three planets.
Unusually, these worlds were in what’s known as an orbital resonance. The closest planet to the star takes 9.11 days to orbit, the next out takes 13.67 days – around 1.5 times that of the inner planet. The furthest planet from the star orbits in 20.52 days, again 1.5 times the orbital time of the middle planet.
“By establishing this pattern of planet orbits, we were able to predict other orbits of planets we hadn’t yet detected,” says Thomas Wilson from the University of Warwick, who
