a super-Earth and five mini-Neptunes.
In a major breakthrough, astronomers have discovered a six-planet system orbiting the star HD 158259, 88 light-years away from Earth. According to astronomers, the star is about the same mass and a little larger than the Sun and it is orbited by six planets: a super-Earth and five mini-Neptunes.
The astronomers monitored the system for seven years and discovered that all six of those planets are orbiting HD 158259 in almost perfect orbital resonance. It is expected that the discovery of the new six-planet system could help the astronomers understand the mechanisms of planetary system formation in a better manner.
Orbital resonance is when the orbits of two planetary bodies around their parent body are closely linked and this is pretty rare in planetary bodies. "Several compact systems with several planets in, or close to, resonances are known, such as TRAPPIST-1 or Kepler-80," explained astronomer Stephane Udry of the University of Geneva.
"Such systems are believed to form far from the star before migrating towards it. In this scenario, the resonances play a crucial part," Udry added.
That's because these resonances are believed to result when planetary embryos in the protoplanetary disc grow and migrate inwards, producing a chain of orbital resonance throughout the system.
"The current departure of the period ratios from 3:2 contains a wealth of information," astronomer Nathan Hara of the University of Geneva in Switzerland said.
"With these values on the one hand, and tidal effect models on the other hand, we could constrain the internal structure of the planets in a future study. In summary, the current state of the system gives us a window on its formation," Hara added.
The findings of the study were published in Astronomy & Astrophysics.
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