Phaeton (hypothetical planet)
Phaeton (alternatively Phaëton) was the hypothetical planet theorized by the obsolete Titius–Bode law to have existed between the orbits of Mars and Jupiter, the destruction of which supposedly led to the formation of the asteroid belt (including the dwarf planet Ceres). The hypothetical planet was named for Phaethon, the son of the sun god Helios in Greek mythology, who attempted to drive his father's solar chariot for a day with disastrous results and was ultimately destroyed by Zeus (= Jupiter).
The hypothesis has been discarded in favor of the accretion theory, which states that the asteroid belt is the remnant of the protoplanetary disk that never formed a planet, and that in this region the amalgamation of protoplanets into a planet was prevented by the disruptive gravitational perturbations of Jupiter during the formative period of the Solar System.
Montana-born Korean War veteran Donald W. Patten proposed a similar idea, that the asteroid belt was formed from the destruction of a Pluto-sized planet which he named Astra (a diminutive of Astraea) that fragmented after entering the Roche limit of Mars (which then had a more eccentric orbit).