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Unique Planetary System Defies Theories of Planetary Formation
The theories of Planetary Formation will never be the same.
ESA’s exoplanet mission, Cheops, revealed a unique planetary system in which five of its six exoplanets are locked in a rare rhythmic dance as they orbit their central star. The sizes and masses of the planets, however, don’t follow such an orderly pattern, challenging current theories of Planet Formation.
Scientists rely on the discovery of increasing numbers of planetary systems to continue to improve the understanding of how planets form and evolve. Although none of the planetary systems discovered so far is like our Solar System.
A striking example is the planetary system called TOI-178, which was found some 200 light-years away in the Constellation of Sculptor.
According to the astronomers, they already expected this star to host two or more exoplanets after observing it with NASA’s Transiting Exoplanet Survey Satellite (TESS).
New, highly precise observations with Cheops, ESA’s Characterising Exoplanet Satellite, now show that TOI-178 harbours at least six planets and that this foreign solar system has a very unique layout. The team, led by Adrien Leleu of University of Geneva and the University of Bern in Switzerland, published their results in the journal Astronomy and Astrophysics.
Planetary System TOI-178
Thanks to data sent by Cheops, the scientists were able to uncover one of the special characteristics of the TOI-178 system: The planets — except the one closest to the star — follow a rhythmic dance as they move in their orbits. This phenomenon is called orbital resonance, and it means that there are patterns that repeat themselves as the planets go around the star, with some planets aligning every few orbits.
According to ESA, a similar resonance is observed in the orbits of three of Jupiter’s moons: Io, Europa, and Ganymede. For every orbit of Europa, Ganymede completes two orbits, and Io completes four (this is a 4:2:1 pattern).
