The December Meteoritics & Planetary Science (vol. 60 #12) is now out, don’t blame me for the holdup:
Kumar Mishra, R. 26Al-26Mg isotope systematics of Ca-Al-rich inclusions and Al-rich chondrules in carbonaceous unequilibrated chondrite Yamato 81020 Art 2759 .70050
Topping, N. Bridges, J. C. Hicks, L. J. et al. Sulfur-bearing serpentine in carbonaceous chondrites Art 2864 .70069
As always, there’s more to the issue than just these two. Much more. However, their relevance swings widely- I make the editorial decision to leave aside those papers only tangentially relating to asteroids, or too deep into the decimal places to be of immediate, significant attention.
The “birth pictures” of the Solar System include aluminum as a sign. The radioactive isotope 26Al heated large asteroids and small planets, causing volcanism and chemical separations, and finally the aluminum decayed to 26Mg. Studying that Al and Mg then establishes our deep history. Some Al (and Mg) got locked into tiny rock clasts- the CAIs (calcium-aluminum rich inclusions), AOAs (amoeboid olivine aggregates), and chondrules. We find these rocks in primitive (unmelted) meteorites, mostly or completely intact. (Planets and some large asteroids retained their radioactive heat, and destroyed such traces.) It implies we should pursue such meteorites and their refractory inclusions if we want to learn of the birth of our Solar System. Kumar Mishra reports on inclusions in an Antarctic meteorite.
Serpentine- a clay mineral- is not found in every meteorite… just the interesting ones. Like other clays, it holds water, and it turns out, organic chemicals that may have jumpstarted life on Earth. One chemical necessary for life as we know it is sulfur; the low melting point of sulfur also makes for interesting reactions, both within the asteroids… and after asteroid mining. Topping et al. try to gain breadth and depth on sulfur in serpentines, in interesting meteorites (plus the sample of Ryugu).