Icarus, the international journal of solar system science, is all about the flow rates this month (if you consider photons or dust a flow). In vol. 422, for 1 Nov 2024:
McGraw, L.E. Emery, J.P. Thomas, C.A. et al. Spatially dependent hydration features on nominall… Art. 116252 .116252
Ahmed, S. Soni, V. Modeling the plasma composition of 67P/C-G at different heliocentric distanc… Art. 116253 .116253
McFadden, L. Brown, P. G. Vida, D. A comparison of fireball luminous efficiency models using ac… Art. 116250 .116250
Garcia, R.S. Fernández-Lajús, E. Di Sisto, R.P. et al. Photometry, rotation period determination a… Art. 116267 .116267
That’s right, hydration features on asteroids. Even the “nominally anhydrous” ones. Previously, water spectra had been detected by ground telescopes on asteroids that shouldn’t have any water. What’s going on? McGraw et al. continue the quest: we see the signs (spectral hydration signatures) on multiple bodies. The hydro-spectra also appear on one side of some bodies, not others: another indication that it’s something at the asteroid, not a telescope flaw or atmospheric interference.
As I mentioned, the Rosetta mission had magnetospheric/plasma instruments, and took fields and particle data at Comet 67P/Churyumov-Gerasimenko. Maybe too much data; the other scientists complained that other mission goals had been short-changed. But Rosetta got the data it got, let’s learn what we can. In particular, Rosetta followed the comet for a while, unlike all other missions.
Meteoroids are the physical evidence of asteroids and comets; meteors (the light and trail phenomena of them as they burn up in our atmosphere) are the visible evidence of meteoroids. If a meteor observation is a type of asteroid/comet study, then how well do we know what we think we know? McFadden et al. attempt to ‘calibrate’ the visible phenomenon with its acoustic phenomenon. Larger meteors, or colloquially ‘fireballs,’ may be big enough to detect via our networks of sound/pressure detectors. Do the two datasets square with each other?
Finally, we have less, and less precise, characterization of a given comet nucleus than we would if it were ‘just’ an asteroid. Asteroids have nicer orbits from a telescopic point of view, and they have no coma to conceal the solid surface. Whenever we can get good data on a comet- its nucleus, or even a good shot of its inner coma- we have a data point to add to our list. As Garcia et al. have.