Cosmic Choreography: Unraveling the 6-Planet Resonance Mystery

Six Planets Circling Their Star in Resonance

An artist’s illustration of the six newly discovered planets circling their star in resonance. Credit: Roger Thibaut (NCCR PlanetS)

Researchers led by Rafael Luque discovered six planets in a rare gravitational resonance around a smaller, cooler star. This unique arrangement, stable since the system’s formation, was identified using data from NASA’s TESS and ESA’s CHEOPS, revealing insights into planetary evolution.

The Discovery

Six planets orbit their central star in a rhythmic beat, a rare case of an “in sync” gravitational lockstep that could offer deep insight into planet formation and evolution.

Key Facts

A star smaller and cooler than our Sun hosts a truly strange family of planets: six “sub-Neptunes” – possibly smaller versions of our own Neptune – moving in a cyclic rhythm. This orbital waltz repeats itself so precisely it can be readily set to music.

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. Credit: Dr. Hugh Osborn, University of Bern


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. Such reliable stability means this system has not suffered the shocks and shakeups scientists might typically expect in the early days of planet formation – smash-ups and collisions, mergers and breakups as planets jockey for position. And that, in turn, could say something important about how this system formed. Its rigid stability was locked in early; the planets’ 3/2 and 4/3 resonances are almost exactly as they were at the time of formation. More precise measurements of these planets’ masses and orbits will be needed to further sharpen the picture of how the system formed.

Fun Facts

The discovery of this system is something of a detective story. The first hints of it came from NASA’s TESS (the Transiting Exoplanet Survey Satellite), which tracks the tiny eclipses – the “transits” – that planets make as they cross the faces of their stars. Combining the TESS measurements, made in separate observations two years apart, revealed an assortment of transits for the host star, called HD 110067. But it was difficult to distinguish how many planets they represented, or to pin down their orbits.

Eventually, astronomers singled out the two innermost planets, with orbital periods – “years” – of 9 days for the closest planet, 14 days for the next one out. A third planet, with a year about 20 days long, was identified with the help of data from CHEOPS, The European Space Agency’s CHaracterising ExOPlanets Satellite.

Then the scientists noticed something extraordinary. The three planets’ orbits matched what would be expected if they were locked in a 3/2 resonance. The next steps were all about math and gravity. The science team, led by Rafael Luque of the University of Chicago, worked through a well-known list of resonances that potentially could be found in such systems, trying to match them to the remaining transits that had been picked up by TESS.

The only resonance chain that matched up suggested a fourth planet in the system, with an orbit about 31 days long. Two more transits had been seen, but their orbits remained unaccounted for because they were only single observations (more than one transit observation is needed to pin down a planet’s orbit). The scientists again ran through the list of possible orbits if there were two additional, outer planets that fit the expected chain of resonances across the whole system. The best fit they found: a fifth planet with a 41-day orbit, and a sixth just shy of 55.

At this point, the science team almost hit a dead end. The slice of the TESS observations that had any chance of confirming the predicted orbits of the two outer planets had been set aside during processing. Excessive light scattered through the observation field by Earth and the Moon seemed to make them unusable. But not so fast. Scientist Joseph Twicken, of the SETI Institute and of the NASA Ames Research Center, took notice of the scattered light problem. He knew that scientist David Rapetti, also of Ames and of the Universities Space Research Association, happened to be working on a new computer code to recover transit data thought to be lost because of scattered light. At Twicken’s suggestion, Rapetti applied his new code to the TESS data. He found two transits for the outer planets – exactly where the science team led by Luque had predicted.

The Discoverers

An international team of researchers led by Rafael Luque, of the University of Chicago, published a paper online on the discovery, “A resonant sextuplet of sub-Neptunes transiting the bright star HD 110067,” in the journal Nature on November 29.

Reference: “A resonant sextuplet of sub-Neptunes transiting the bright star HD 110067” by R. Luque, H. P. Osborn, A. Leleu, E. Pallé, A. Bonfanti, O. Barragán, T. G. Wilson, C. Broeg, A. Collier Cameron, M. Lendl, P. F. L. Maxted, Y. Alibert, D. Gandolfi, J.-B. Delisle, M. J. Hooton, J. A. Egger, G. Nowak, M. Lafarga, D. Rapetti, J. D. Twicken, J. C. Morales, I. Carleo, J. Orell-Miquel, V. Adibekyan, R. Alonso, A. Alqasim, P. J. Amado, D. R. Anderson, G. Anglada-Escudé, T. Bandy, T. Bárczy, D. Barrado Navascues, S. C. C. Barros, W. Baumjohann, D. Bayliss, J. L. Bean, M. Beck, T. Beck, W. Benz, N. Billot, X. Bonfils, L. Borsato, A. W. Boyle, A. Brandeker, E. M. Bryant, J. Cabrera, S. Carrazco-Gaxiola, D. Charbonneau, S. Charnoz, D. R. Ciardi, W. D. Cochran, K. A. Collins, I. J. M. Crossfield, Sz. Csizmadia, P. E. Cubillos, F. Dai, M. B. Davies, H. J. Deeg, M. Deleuil, A. Deline, L. Delrez, O. D. S. Demangeon, B.-O. Demory, D. Ehrenreich, A. Erikson, E. Esparza-Borges, B. Falk, A. Fortier, L. Fossati, M. Fridlund, A. Fukui, J. Garcia-Mejia, S. Gill, M. Gillon, E. Goffo, Y. Gómez Maqueo Chew, M. Güdel, E. W. Guenther, M. N. Günther, A. P. Hatzes, Ch. Helling, K. M. Hesse, S. B. Howell, S. Hoyer, K. Ikuta, K. G. Isaak, J. M. Jenkins, T. Kagetani, L. L. Kiss, T. Kodama, J. Korth, K. W. F. Lam, J. Laskar, D. W. Latham, A. Lecavelier des Etangs, J. P. D. Leon, J. H. Livingston, D. Magrin, R. A. Matson, E. C. Matthews, C. Mordasini, M. Mori, M. Moyano, M. Munari, F. Murgas, N. Narita, V. Nascimbeni, G. Olofsson, H. L. M. Osborne, R. Ottensamer, I. Pagano, H. Parviainen, G. Peter, G. Piotto, D. Pollacco, D. Queloz, S. N. Quinn, A. Quirrenbach, R. Ragazzoni, N. Rando, F. Ratti, H. Rauer, S. Redfield, I. Ribas, G. R. Ricker, A. Rudat, L. Sabin, S. Salmon, N. C. Santos, G. Scandariato, N. Schanche, J. E. Schlieder, S. Seager, D. Ségransan, A. Shporer, A. E. Simon, A. M. S. Smith, S. G. Sousa, M. Stalport, Gy. M. Szabó, N. Thomas, A. Tuson, S. Udry, A. M. Vanderburg, V. Van Eylen, V. Van Grootel, J. Venturini, I. Walter, N. A. Walton, N. Watanabe, J. N. Winn and T. Zingales, 29 November 2023, Nature.
DOI: 10.1038/s41586-023-06692-3

2 Comments on "Cosmic Choreography: Unraveling the 6-Planet Resonance Mystery"

  1. dr mehrdad kesiri | December 1, 2023 at 11:20 am | Reply

    Hello, why do planets that are farther from the sun rotate slower than planets that are closer to the sun? To two planets close to the sun such as Venus and Mercury. In the past, several planets that came from the big arm of the galaxy hit Venus towards the sun, and some planets also hit Mercury and caused Mercury and Venus to rotate much slower than Earth!? Shouldn’t the planets that are close to the sun go around them faster because of the strong gravitational force of the sun? Venus and Mercury go around the sun faster than Earth and Mars. Mercury goes around the sun at a speed of 172 thousand kilometers per hour, but when a heavy object hits Mercury The speed of Mercury has not decreased around the sun, but the rotation of Mercury around itself has decreased due to the many collisions of planets
    All the stars are in motion due to the force of gravity between the bodies. The greater the mass and weight of the body, the stronger the magnetic currents are dispersed around the sun. Every second, trillions of trillions of bargamma electromagnetic waves from the sun hit the surface of the planets, which causes the planets to rotate around themselves. And it also causes the planets to orbit around the sun. Planets that are closer to the sun’s magnetic field face more and more intense waves. That’s why Mercury orbits the sun faster than Earth and Mars. Why does Mercury take 58 days to make one revolution? It revolves around itself, but a full day on Earth lasts 24 hours, but on Mercury, a full day lasts 1393 hours.
    The reason is that Jupiter is far away from the sun and is 778 million kilometers away from the sun. Why does it revolve around itself in less than 24 hours? What is the reason? A day and night lasts nine and a half hours and 9.5 hours in Jupiter.
    The reason for this is that they hit Jupiter, but very small planets hit Mercury
    Whenever a star collides with a planet, the planet spins faster
    Whenever a planet collides with a planet, the planet slows down or reverses
    The story of the star and the planet is the rule of two gears that rotate against each other but overlap each other, but the greater the force that turns one of the gears, the same rotation force is transferred to the gear.
    When a star collides with a planet, because the stars revolve around the planet, when the star hits the planet’s surface, all the force of the star’s rotation is transferred to the planet’s surface and to Jupiter’s surface. At least dozens of stars that were a hundred times smaller than the sun collided and caused Jupiter revolves around itself at a speed of 45,000 thousand kilometers. If the stars of the arm of the galaxy had not hit Jupiter, Jupiter would now rotate one hundred percent slower than the Earth. In order, the planets that are farthest from their stars rotate slower than the nearest planets. Mars is slower than the Earth because it is far from the Sun. The farther the planets are from their star, the slower the rotation of that planet around itself, and the slower the rotation of that planet around the star in the orbit around the star.
    But if the planet collides with the planet, the speed of the planet will either stop or slow down if the number of collisions with the planet is more like Venus.
    That planet reverses. Hundreds of planets collided with Venus. Now Venus takes 243 days to revolve around itself.dr kesiri n…r mobil 00989332197646 mehrdad u sent s m s thank you

  2. … resolution!!!

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