The Meteoritics & Planetary Science issue for March (vol. 61 #3) is finally up:
Dobrică, E. Krot, A. N. Brearley, A. J. Shock metamorphic effects in Itokawa phosphates: A comparison with megaregolith-derived meteorites Pg 351 .70102
Seifert, L. B. Erickson, T. M. Keller, L. P. et al. Apatite in Bennu samples indicates multiple stages of aqueous alteration Pg 504 .70093
Standard disclaimer: Everything in the issue is, by various metrics, at least a little relevant for an asteroid blog. I’ve just picked the best two. You can read the whole issue if you feel so inclined.
Phosphates: interesting for multiple reasons, and not just as a vital source of phosphorus for life. Phosphates also store water (certainly necessary for life), yet are susceptible to heat. The presence of phosphates (here, merrillites and apatites) indicates formation in a water solution, during the early history of the Solar System when a subset of asteroids were mudballs. Literal mudballs.
At Itokawa, the Hayabusa probe recovered trace phosphates among the dust particles. These particles, of course, were at the surface of Itokawa, and record the surface environment. Dobrică et al. detail the effects of space exposure at Itokawa, as witnessed by the soft phosphates from the surface regolith.
At Bennu (rich in phosphates), the OSIRIS-REx probe gathered more material, more of which was phosphates, due to the greater and longer mudball phase of that asteroid. The specific forms of merrillites and apatites, their heteroelements, crystallinities, etc. all give us clues as to what happened at Bennu during that fluid phase. Rich in phosphates, and rich in history too.