Is something happening at Nature Group, something positive? Three days, four items in NatAstronomy:
Pilorget, C. Baklouti, D. Bibring, J.-P. et al. 25 September 2024 Phosphorus-rich grains in Ryugu samples with major biochemical potential s41550-024-02366-w
Bennu (via the OSIRIS-REx sample) has lots of phosphates, a very surprising amount. While it was known that carbonaceous-chondrite meteorites, and the Ryugu sample (via Hayabusa2) had some phosphates, Bennu’s [PO4]– was simply off the charts. And now it’s Ryugu’s turn in the spotlight: Ryugu phosphates include ammoniated material, X[NH4][PO4]. This means- along with the water, organics, and sulfides- Ryugu is a nontrivial source of the key ingredients for life. Those are “CHNOPS”- carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur. Is “Ryugu” the answer in search of a question?
Genge, M. J. Almeida, N. V. van Ginneken, M. et al. 26 September 2024 Evidence from 162173 Ryugu for the influence of freeze–thaw on the hydration of asteroids s41550-024-02369-7
We knew C-asteroids had water, from the C-meteorites. We also had indications that this water is still here, not ancient but since lost (Turner et al. 2021: “Carbonaceous chondrite meteorites experienced fluid flow within the past million years”). Even aside from directly measuring the water retained by Ryugu samples, we now know that water was not just present, but a geological driver in these bodies.
Potiszil, C. Ota, T. Nakamura, E. 26 September 2024 Reconciling remote-sensing estimates of Ryugu’s albedo with laboratory measurements s41550-024-02372-y
When the Hayabusa2 craft approached and orbited the NEO, Ryugu appeared “dark” (low albedo), to the point of us expecting super-high carbon content. The samples showed a more moderate carbon level, closer to carbonaceous meteorites, not comet samples. What’s going on here? As part of the mission, it behooves us to settle what we saw, what we thought we saw, and why the two differ. When we examine other asteroids, we shouldn’t make the same mistake (such as it is) again. Is it a faulty instrument? Unfortunate, but fixable if we try. Here, it seems grain effects cause a visibility bias… maybe.
Finally, a perspective article:
Shen, J. Liu, C. Pan, Y. et al. 27 September 2024 Follow the serpentine as a comprehensive diagnostic for extraterrestrial habitability s41550-024-02373-x
Well, obviously. Serpentine makes up, say, a third to perhaps a half of many carbonaceous meteorites (the CI- and CM-groups), and these are water-rich, organic-rich, sulfur-rich, etc. In other words, these are answers, maybe to the question of habitability.
[H/T to Edgar Rivera-Valentín for the cite.]