Jeremy Couturier

2025-present
Mostly Geneva, some Quebec too

3-planet resonances

Resonances in physics are all over the place, and resonances between planets can shape the dynamics of planetary systems. 2-planets resonances are fairly easy to grasp. If planet A has an orbital frequency twice as large as planet B, then planets A and B are in a 1:2 resonance. If nA and nB are the orbital frequencies of A and B, this resonance is often written nA - 2 nB = 0. But resonances can also occur between three planets A, B and C. For example, the three inner planets of the system K2-138 are in the 3-planet resonance 2 nA - 5 nB + 3 nC = 0.

Artist impression of K2-138 generated by deepai

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I am currently working specifically on these resonances at the Observatory of Geneva. So far, I have implemented a module to the python algebraic manipulator celeries, called PerHam3pla, able to study these resonances in an analytical manner. While my work on the matter is not published yet, some of it is already synthetized in this PDF.

I am proving that when close to their host star, 3-planet resonances are disrupted by tides, in a characteristic timescale that I have obtained analytically. This result, combined with the known age of K2-138, can constrain the tidal parameters of planets in this system and others.

See another work