The animation below is a recreation of the movements of the planets in the star system called TOI-178. The system is surprisingly nearby, approximately 200 light-years away from our solar system. All but one of the six planets of the TOI-178 are locked in unusual resonance orbits.
As the planets orbit the star, they make patterns that repeat themselves rhythmically, with some planets aligning every few orbits. The European Space Agency has stated that the planets have been identified in the data collected by its Cheops planet-watcher, a telescope in space.
Astronomers using data from NASA's Transiting Exoplanet Survey Satellite (TESS) have detected three planets around a star called TOI-178 initially. And as scientists looked more carefully at these findings, they found that the worlds appeared to be holding time against each other. So they enlisted a few more instruments-and found that the system hosts at least six planets, five of them ticking orbits in rhythm with the others.
Driven by the peculiar TESS data showing three planets in a unique rhythm, the scientists behind the new research enlisted additional instruments resulting in a dozen days of observation time with the CHEOPS telescope.
The innermost of them, it turns out, maneuvers to a different rhythm, but the outer five orbits in sync with each other. For any full orbit of the outer world, the next completes three-quarters of an orbit, the middle world in a chain makes two circles, then a planet that makes three orbits, and then a planet that makes six orbits; the planets line up periodically along the way, creating a peculiar pattern in the original TESS data.
Not only could astronomers detect new planets and figure out a complex sequence of orbits, but scientists could also analyze the planets themselves, discovering that these worlds vary from 1.1 to 3 times the size of the Earth, but with a range of densities, rendering them a strange combination of rocky super-Earths and gaseous mini-Neptunes.
Scientists believe that there might be other planets sharing the same sequence of orbital alignments, but the detection of these worlds may take longer periods of observation. Fortunately, since the star itself is so light, the system is pretty easy to study; in fact, researchers are looking forward to the data that NASA's James Webb Space Telescope and the European Extremely Large Telescope will be able to gather about the system any time it begins operating.
This research is presented in a paper published on Jan. 25 in the journal Astronomy & Astrophysics.
