The 1 Oct issue of Earth and Planetary Science Letters (vol. 667) has:
Spitzer, F. Hopp, T. Burkhardt, C. et al. The evolution of planetesimal reservoirs revealed by Fe-Ni isotope anomalies in differentiated meteorites Art 119530 .2025.119530
I’ve said it before, I’ve said it many a time. Undifferentiated asteroids (ones that never melted) and their fragments, undifferentiated meteorites, bear traces from the history of the Solar System. Studying these asteroids and fragments then tells us of our origin, our place, and our very nature. Here, Spitzer et al. attempt to piece together an early stage of our Solar System’s formation: the starting sub-reservoirs in the protosolar disk, which then clumped together into the seed materials for everything else that followed. It’s clear there were at least two different sources in the early disk: an inner reservoir, forming high-temperature grains and asteroids, and an outer, low-temperature reservoir.
But these grains and asteroids formed into large bodies pretty quickly. These large asteroids (planetesimals) retained their heat, and melted. Tracing the resulting magma in these second-generation Solar System bodies can tell us more details on what their starting materials had been. The second generation of asteroids seems, so far, to have gathered fairly diverse material, because they’re fairly blended and similar to each other. One oddity, though, is that they don’t look like CI chondrite meteorites (and therefore, Bennu and Ryugu, which had gathered from CI-like material).