Extended Data Fig. 6: GB ejecta delivered to Earth, normalized with the background lunar meteorite flux.
From: Asteroid Kamo‘oalewa’s journey from the lunar Giordano Bruno crater to Earth 1:1 resonance
It has been estimated that the GB ejecta is comparable to the total lunar ejecta produced by other craters over 10 Myr42, thus the background lunar ejecta per Myr is about one-tenth of the GB total ejecta. Assuming the same delivery efficiency (Earth collision fraction over time) as the GB ejecta, we can integrate the product of the ejecta volume and the delivery efficiency of all previous craters, to estimate the background flux delivered to Earth per Myr. The result shows a ten-fold spike of GB meteorites than the background flux in the first Myr after GB formation (several million years ago). However, this spike is currently unobservable due to the short terrestrial preservation period of lunar meteorites, which only lasts a few hundred thousand years8. Presently, GB ejecta contributes to roughly 10% of the background flux of lunar meteorites, implying that our current collection of lunar meteorites likely contains only a handful of GB ejecta, for example, the possible GB meteorites Yamato-82192/82193/8603242.
