February’s “issue” (all-digital) of Monthly Notices of the Royal Astronomical Society (vol. 536) is done, and it’s ‘volatile-rich’:
Volume 536, Issue 4, February 2025
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Volume 537, Issue 1, February 2025
Longobardo, A. Angrisani, M. Palomba, E. Photometry of (162173) Ryugu and its artificial crater as inferred by Hayabusa2/ONC images Pages 127–133 staf003
Rezac, L. Zhao, Y. Evolving properties of pits on 67P/C-G due to illumination induced mass-loss – I. Isolated shape morphology Pages 217–228 stae2729
Volume 537, Issue 2, February 2025
Shestakova, L. I. Spassyuk, R. Omarov, C. Thermal stresses as a possible mechanism for initiating the destruction of comet Shoemaker–Levy 9 Pages 2151–2159 staf081
The Hayabusa2 mission punched a small crater into asteroid Ryugu (the SCI experiment- Small Carry-on Impactor), exposing fresh (subsurface) material. What is the nature of this alteration, and what materials do we then see? Longobardo et al. are on it: some observations match expectations, some have weird effects. Simply being a close-up means observations differ from ground (unresolved) data.
Speaking of craters- or ‘craters’- comets have “pits,” first seen by the Stardust mission on comet Wild 2. These are surface depressions, which cannot be conclusively identified to be impact craters. The possibility exists that these are actually mass wasting by loss of volatiles, or loss from cryovolcanic events, or even something we don’t even know about yet. The Rosetta craft, with its orbital rendezvous of its target (unlike all previous, flyby comet missions), had the so-far unique ability to track surface features as they changed. What did Rosetta see at comet Churyumov-Gerasimenko’s pits?
The comet Shoemaker-Levy 9 did not get orbited by a human probe; it got into orbit around Jupiter, when that planet’s immense gravity captured it from the wider Solar System. Once captured, S-L9 broke into multiple pieces; conventional wisdom is that the tidal force of that immense gravity (the difference between pull on the near side of the comet, versus the force on the far side) stressed the comet nucleus beyond its strength limit. Or did it? As a comet, S-L9 is a mixture of rock, organics, and frozen volatiles. A hypothesis is that those deposits of frozen water and other volatiles let go under the new conditions. Shestakova et al. explore what contribution this could have made towards breaking up the comet.