Scientists discover rare six-planet system that moves in synchrony

Transiting Exoplanet Survey Satellite (TESS) [image credit: NASA]

This system looks like a prize winner for resonance. For no obvious reason Phys.org calls it ‘strange’ synchrony. Planets orbiting near their star (orbit periods from 9 to 55 days in this example) are bound to be strongly influenced by it, in the same way moons close to planets can be.
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Scientists have discovered a rare sight in a nearby star system: Six planets orbiting their central star in a rhythmic beat, says Phys.org.

The planets move in an orbital waltz that repeats itself so precisely that it can be readily set to music.

A rare case of an “in sync” gravitational lockstep, the system could offer deep insight into planet formation and evolution.

The analysis, led by UChicago scientist Rafael Luque, was published Nov. 29 in Nature.

“This discovery is going to become a benchmark system to study how sub-Neptunes, the most common type of planets outside of the solar system, form, evolve, what are they made of, and if they possess the right conditions to support the existence of liquid water in their surfaces,” said Luque.

A rare resonance
The six planets orbit a star known as HD110067, which lies around 100 light-years away in the northern constellation of Coma Berenices.

In 2020, NASA’s Transiting Exoplanet Survey Satellite (TESS) detected dips in the star’s brightness that indicated planets were passing in front of the star’s surface. Combining data from both TESS and the European Space Agency’s CHaracterizing ExOPlanet Satellite (Cheops), a team of researchers analyzed the data and discovered a first-of-its-kind configuration.

While multi-planet systems are common in our galaxy, those in a tight gravitational formation known as “resonance” are observed by astronomers far less often.

In this case, the planet closest to the star makes three orbits for every two of the next planet out—called a 3/2 resonance—a pattern that is repeated among the four closest planets. Among the outermost planets, a pattern of four orbits for every three of the next planet out (a 4/3 resonance) is repeated twice.

And these resonant orbits are rock-solid: The planets likely have been performing this same rhythmic dance since the system formed billions of years ago, the scientists said.
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“We think only about one percent of all systems stay in resonance, and even fewer show a chain of planets in such configuration,” said Luque. That why HD110067 is special and invites further study: “It shows us the pristine configuration of a planetary system that has survived untouched.”

Full article here.
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NASA – Discovery Alert: Watch the Synchronized Dance of a 6-Planet System

NASA: This animation shows six “sub-Neptune” exoplanets in rhythmic orbits around their star – with a musical tone as each planet passes a line drawn through the system. The line is where the planets cross in front of (“transit”) their star from Earth’s perspective. In these rhythms, known as “resonance,” the innermost planet makes three orbits for every two of the next planet out. Among the outermost planets, a pattern of four orbits for every three of the next planet out is repeated twice. Animation credit: Dr. Hugh Osborn, University of Bern