Astronomers Discovered A Star System Near us With Six Sub-Neptunes In Resonance
A group of researchers using the TESS and Cheops space telescopes solved the mystery of a rare star system with six planets.
At the center of the star system is a sun-like star called HD110067, and it is observed in the constellation Coma Berenices. Orbiting it are six planets larger than Earth but smaller than Neptune – sub-Neptunes, which are often found in the orbits of sun-like stars in the Milky Way. The planets, designated b through g, rotate in orbital resonance. For every six orbits of planet b, which is closest to the star, planet g makes exactly one revolution. While planet c makes three orbits around the star, planet d makes two. And when planet e makes four revolutions, planet f makes three. This harmonic rhythm creates a resonant chain in which they all sometimes line up in a row. The star system formed about a billion years ago, very little has changed in the intervening time, and this discovery could shed light on the evolution of planets and the origin of the sub-Neptunes common in our galaxy.
Additional observations of the star, designated HD 110067, using TESS and the European Space Agency’s CHEOPS telescope in 2022 not only confirmed the presence of six transiting sub-Neptunes, but also that these cosmic components exert gravitational influence on each other as they rotate in a specific pattern. Astronomers call this a resonance, a configuration that rarely persists as a multiplanet system evolves over time. The planets of our solar system, for example, are not in resonance.
A family of six gaseous worlds orbiting a Sun-like star will soon help astronomers better understand how planetary systems like ours formed and evolved.
