Evidence item

Using Bayesian inference, we find that bulk silicate Earth is best reproduced by ≳75% contribution from two protoplanets formed via pebble accretion, supplemented by up to ∼25% material from planetesimals that are compositionally akin to the asteroid Vesta. Using instead a planetesimal volatile-depletion curve that is not observed among known meteorite parent bodies would allow the planetesimal contribution to reach 40+15−14%. In comparison, bulk silicate Mars reflects 27±5% pebble-accreted material and 73±5% Vesta-like planetesimals.