What if, instead of forming an asteroid belt, the solar system had produced at planet between Mars and Jupiter? How would that have formed, and what would be different?
A new paper explores this hypothesis, Planet Artemis: the case for the formation and delayed destruction of a fifth Solar System terrestrial planet
We investigate the possibility that a fifth terrestrial planet (nicknamed “Artemis”) may have formed beyond Mars’ orbit, in what is now the asteroid belt. Artemis could have formed in a region that was stable before the giant planets’ shift, but unstable thereafter, probably between 1.8-2.2 AU. We simulate the giant planets’ orbital shift to explore Artemis’ demise, varying Artemis’ mass and starting location. In each simulation, the giant planets’ eccentricity jump causes a increase in the terrestrial planets’ eccentricities, sometimes causing their orbits to cross and collisions to occur. In simulations where Artemis is 1/3 Earth mass or larger, Mars is typically destroyed via ejection or a collision, and Mercury often falls into the Sun. In cases with a Mars-mass Artemis, either Mars or Artemis is ejected. However, the remnant terrestrial planets often have higher orbital eccentricities than observed today because of multiple close encounters. Rapid destruction of Artemis is needed to keep terrestrial eccentricities low.
I did something like this (but much scaled down with no simulation) in grad school for my planetary sciences class. I used the Virial Theorem to show that in most cases the binding energy for the solar system causes ejection of the protoplanet, but this anlysis is more subtle and shows cases where the planet either fails to form or is quickly destroyed.
Destroying a planet is no simple feat. The amount of energy required, for example, to destroy the current Earth would take approximately the *entire* output of the Sun for 3 weeks.
No comments:
Post a Comment