FormingWorlds / PROTEUS

Coupled atmosphere-interior framework to simulate the temporal evolution of rocky planets.
https://proteus-code.readthedocs.io
Apache License 2.0
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An estimation for a planet/star system's spin-orbit resonance regime #63

Open nichollsh opened 5 months ago

nichollsh commented 5 months ago

Currently, we provide the orbital distance and stellar mass as input parameters. This provides the length of the planet's year. We also input the zenith angle and heat redistribution factor, which allow us to handle resonant and asynchronously rotating cases.

Determining which planets are spin-orbit resonant and which are not is far from trivial, so in some cases it isn't clear which input parameters should be chosen. It would be helpful to implement a simple model for determining which state a given configuration is likely to enter into. This will fall short of a robust model which actually estimates the tidal stress on the planet and thereby more realistically determines the rotational regime.

This could be included in the main code itself, or simply as a tool which provides information to the user before the model is executed.

nichollsh commented 5 months ago

One simple way to approach this is to calculate the locking time-scale. This would require some estimations (guesses) for the properties of the planet (e.g. of its rigidity and ability to dissipate energy imparted by the tidal stresses).

https://en.wikipedia.org/wiki/Tidal_locking#Timescale

nichollsh commented 5 months ago

See also: https://www.aanda.org/articles/aa/full_html/2011/04/aa15809-10/aa15809-10.html