A bit light issue of Astronomy & Astrophysics for April (vol. 708):
Pal, I. Jadhav, M. Shulaker, D. Z. et al. The stellar origins of 96Zr excesses in presolar graphites from the Murchison meteorite A42 202556719
Salo, H. Sicardy, B. Rings around irregular bodies – II. Numerical simulations of the 1/3 spin-orbit resonance confinement and applications to Chariklo A9 202556946
Spurný, P. Borovička, J. Deepest ever photographed Geminid with small but non-negligible terminal mass A34 202659084
The chondrite meteorites have never been melted. That means they preserve the history of the early Solar System, including pre-history: presolar grains that had been interstellar dust, now trapped within these 4.6 billion year old rocks. Some of these preserved grains are crystals of zircon, which are particularly durable and long-lasting. The various zirconium isotope levels within them can then be used as tracers, for over 4.6 billion years of history.
Less aged, but still elegant in form: rings. Yes, it was a surprise to me along with most people when rings around small bodies (centaurs) were announced years ago. Everything’s far apart in the outer Solar System, so small bodies are less perturbed by the gravities of the giant planets. Still, there’s a dynamics problem here. Either Chariklo’s rings formed very recently (as the Solar System goes), and will scatter ‘quickly’. That, or there’s some gravitational/orbital effect that is stabilizing these rings. Salo et al. attempt the latter approach. Maybe some Chariklo satellite we don’t see?
A meteor, per se, is the light show made by a meteoroid hitting our atmosphere, and burning up. A meteorite is the surviving rock that didn’t fully burn up, and reaches the ground. In between, we have terminal particles- the ashes of a would-be meteorite. Spurný and Borovička, in recording meteor showers, found an exceptional Geminid meteor (grains shed by active asteroid (3200) Phaethon) that came close(?) to hitting ground. We know some things about Phaethon (and we’ll know more after Japan’s DESTINY+ flyby), but til then we’ll have to study Geminid meteors.