Planet V

Chambers and Lissauer presented the results of initial tests of this hypothesis during the 33rd Lunar and Planetary Science Conference, held from March 11 through 15, 2002.

The fifth terrestrial planet began on a low-eccentricity orbit between Mars and the asteroid belt with a semi-major axis between 1.8 and 1.9 AU.

After an initial decline the number of particles on Earth-crossing orbits increased after Planet V entered the inner asteroid belt a pattern consistent with the LHB.

[2] In a later article published in the journal Icarus in 2007, Chambers reported the results of 96 simulations examining the orbital dynamics of the Solar System with five terrestrial planets.

Their work was the first to focus on the magnitude of the bombardment caused by Planet V. Brasser and Morbidelli calculated that to create the Late Heavy Bombardment Planet V would have to remove 95% of the pre-LHB main asteroid belt or 98% of the inner asteroid belt (semi-major axis < 2.5 AU).

The authors noted that the lack of present-day detection of the remnants of these belts places a significant constraint on this hypothesis, requiring that they be 99.99% depleted before Planet V was lost.

[4] An impact of Planet V onto Mars, forming the Borealis Basin has recently been proposed as an explanation for the Late Heavy Bombardment.