Enyo and Bellona (originally A and B respectively) were two super-Earth (or even supergiant) planets theorized by Michael Woolfson as part of his Capture theory on Solar System formation. They were supposedly the Solar System's two original innermost planets but collided shortly after their formation.
In the first version of the hypothesis, the collision ejecta A/Enyo (save its moons Mars, the Moon, Pluto, and the other dwarf planets) out of the Solar System and shatters B/Bellona to form the Earth, Venus, Mercury, asteroid belt, and comets.
In an updated version, Enyo and Bellona have masses greater than Jupiter. They collide and explode due to the collision causing deuterium fusion to occur within the planets. Venus and Earth develop from the cores of Enyo and Bellona respectively.
| Hypothetical Bodies in the Solar System | ||
|---|---|---|
| Hypothetical Planets | Inner Solar System | Vulcan • Counter-Earth • Nibiru • Theia • Phaeton • Enyo and Bellona • Krypton |
| Outer Solar System | Fifth Giant • Unnamed ancient Super-earth • Triton’s Binary Partner • Planet 9 • Planet 10 • Tyche • Nemesis | |
| Hypothetical Moons | Inner Solar System | Disproven Moons of Mercury • Neith • Petit's moon • Waltemath's moons • Moons of Pallas • Moon of Hebe |
| Outer Solar System | Chiron • Chrysalis • Themis • Sedna I • Varuna I • Herschel's Moons | |
| Other Hypothetical Objects | Hypothetical Regions | Vulcanoid Belt • Hills Cloud • Oort Cloud |
| Hypotheses for Explanation of Occurrences | Hypotheses | Giant impact hypothesis • Himalia Crash Theory |