Orbital stability of compact three-planet systems, I: Dependence of system lifetimes on initial orbital separations and longitudes
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Orbital stability of compact three-planet systems, I : Dependence of system lifetimes on initial orbital separations and longitudes. / Lissauer, Jack J.; Gavino, Sacha.
In: Icarus, Vol. 364, 114470, 08.2021.Research output: Contribution to journal › Journal article › Research › peer-review
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TY - JOUR
T1 - Orbital stability of compact three-planet systems, I
T2 - Dependence of system lifetimes on initial orbital separations and longitudes
AU - Lissauer, Jack J.
AU - Gavino, Sacha
PY - 2021/8
Y1 - 2021/8
N2 - We explore the orbital dynamics of systems consisting of three planets, each as massive as the Earth, on coplanar, initially circular, orbits about a star of one solar mass. The initial semimajor axes of the planets are equally spaced in terms of their mutual Hill radius, which is equivalent to a geometric progression of orbital periods for small planets of equal mass. Our simulations explore a wide range of spacings of the planets, and were integrated for virtual times of up to 10 billion years or until the orbits of any pair of planets crossed. We find the same general trend of system lifetimes increasing exponentially with separation between orbits seen by previous studies of systems of three or more planets. One focus of this paper is to go beyond the rough trends found by previous numerical studies and quantitatively explore the nature of the scatter in lifetimes and the destabilizing effects of mean motion resonances. In contrast to previous results for five-planet systems, a nontrivial fraction of three-planet systems survive at least several orders of magnitude longer than most other systems with similar initial separation between orbits, with some surviving 1010 years at much smaller orbital separations than any found for five-planet systems. Substantial shifts in the initial planetary longitudes cause a scatter of roughly a factor of two in system lifetime, whereas the shift of one planet's initial position by 100 m along its orbit results in smaller changes in the logarithm of the time to orbit crossing, especially for systems with short lifetimes.
AB - We explore the orbital dynamics of systems consisting of three planets, each as massive as the Earth, on coplanar, initially circular, orbits about a star of one solar mass. The initial semimajor axes of the planets are equally spaced in terms of their mutual Hill radius, which is equivalent to a geometric progression of orbital periods for small planets of equal mass. Our simulations explore a wide range of spacings of the planets, and were integrated for virtual times of up to 10 billion years or until the orbits of any pair of planets crossed. We find the same general trend of system lifetimes increasing exponentially with separation between orbits seen by previous studies of systems of three or more planets. One focus of this paper is to go beyond the rough trends found by previous numerical studies and quantitatively explore the nature of the scatter in lifetimes and the destabilizing effects of mean motion resonances. In contrast to previous results for five-planet systems, a nontrivial fraction of three-planet systems survive at least several orders of magnitude longer than most other systems with similar initial separation between orbits, with some surviving 1010 years at much smaller orbital separations than any found for five-planet systems. Substantial shifts in the initial planetary longitudes cause a scatter of roughly a factor of two in system lifetime, whereas the shift of one planet's initial position by 100 m along its orbit results in smaller changes in the logarithm of the time to orbit crossing, especially for systems with short lifetimes.
KW - Exoplanets
KW - Numerical
KW - Planetary systems
KW - Planets and satellites
KW - Dynamical evolution and stability
KW - RESONANCE OVERLAP
KW - PLANETS
KW - MASS
KW - INSTABILITY
U2 - 10.1016/j.icarus.2021.114470
DO - 10.1016/j.icarus.2021.114470
M3 - Journal article
VL - 364
JO - Icarus
JF - Icarus
SN - 0019-1035
M1 - 114470
ER -
ID: 270618115