A unique planetary system located in 200 light-The year from Earth hosts five exoplanets with closed orbits together in repeating patterns, albeit five different sizes and densities. The discovery is challenging astronomers’ Perceptions of the types of planetary systems may exist and how they are formed.
One of the six exoplanets in orbit around the star TOI-178 have orbital resonances with each other in 18: 9: 6: 4: 3 The research Published today in Astronomy and Astrophysics. So for every 18 orbits created by the innermost of these five exoplanets, the next planet along the series will complete nine orbits during exactly the same period. The third will complete six classes, and so on. The video below provides a demonstration of the process in action.
The difference of the six exoplanets (shown along a blue orbital path) is not in resonance with the others, although it may have been in the past. In the animation above, rhythmic patterns are represented by red pulses and a chime sound (In pententonic scale), Which is triggered when each exoplanet completes either a full orbit. As the video suggests, two or more exoplanets often trigger chimes, resulting in orbital resonance. The new study was led by CHEOPS fellow Adrian Leleu at the University of Geneva.
When Leleau, a dynamist (an expert in celestial mechanics) and his colleagues first Observing the TOI-178 system, they thought they saw two planets orbiting around the host star in the same orbit, but this result was inconclusive. Scientists decided to make follow-up observations using T.He belongs to the European Space Agency CHEOPS satellite and ground-based ESPRESSO instrument at European Southern Observatory Very large telescope, other than this ahead The generation Transit Survey And speculos The projectsBoth in Chile. All tThe Hays instruments allowed the team to detect and characterize six exoplanets, which they did using the transit method (see) When a planet passes through the front) and tilts the host star by measuring Host star wobble
All six exoplanets are in close proximity to the central star, it takes about two days to make the nearest planet a full orbit. Farthest rotation About 20 days. No one is inside the habitable zone, the Goldilocks area around the star where liquid water (and thus life) would be possible. Five of the six exoplanets are locked in perfect resonance, such as some planets Align every few classes. The 18: 9: 6: 4: 3 series is the longest discovery ever.
Orbital resonance occurs when the orbiting bodies exert periodic gravitational effects on each other. In our solar system, Jupiter’s moons Io, Europa and Ganymede are in a 4: 2: 1 resonance.
The TOI-178 is interesting for several reasons, indicating long-term stability with orbital resonance.
“From our understanding of planetary structures, the chain of resonance often occurs in the early stages of planetary formation,” When the star is still surrounded by a gaseous disk, ”Leleu explained in an email. “However, during the billions of years after formation, many things can happen and most systems fall out of resonance. This can happen slowly, due to which [gravitational] For example, or violently tidal effects Due to instability and planetary collision / ejection. “
He said that only five other star systems have chains associated with four or more planets, which are not very many. Astronomers consider these planetary systems to be rare and quite young.
“What is unique to TOI-178 is not only the orbital configuration, but also the planetary structure,” Leleau said. As a result, there is a challenge in our understanding of how planets are formed and developed.
Actually, planets are between one and three tSimulates the shape of the earth But is The mass of the Earth ranges from 1.5 to 30 times. So while their orbital configurations are neat, their compositions are not. For example, a planet is a super-Earth, but its immediate neighbor is-The vastness of density ice similar to that of Neptune. We don’t see that kind of thing here and there.
According to Leleau, the theory states that the farther away the planets are from their star, the lower its density. But here it is not so. “In TOI-178, this is only true for the two inner planets which are rocky, but then the density of the third star is much lower, then planets 4 and 5 are more dense, and then planet 6 is once again more fluffy. Is, “he said.
Astronomers now have to find out how the system was formed, what is involved Some of the planets Was formedget out off And slowly Have become Inwards.
Interestingly, TOI-178 could host other, more distant Planet, but They have not been revealed yet. Looking ahead, ESO’s upcoming ultra-large telescope later this year, which should be operational later this year, may be able to learn more about this odd star system.