Найдено научных статей и публикаций: 1, для научной тематики: Irregular moons
1.
Sergey A. Astakhov, Andrew D. Burbanks, Stephen Wiggins & David Farrelly
- Nature , 2003
It has been thought1–3 that the capture of irregular moons—with
non-circular orbits—by giant planets occurs by a process in
which they are first temporarily trapped by gravity inside the
planet’s Hill sphere (the region where planetary gravity dominates
over solar tides4). The capture of the moons i...
It has been thought1–3 that the capture of irregular moons—with
non-circular orbits—by giant planets occurs by a process in
which they are first temporarily trapped by gravity inside the
planet’s Hill sphere (the region where planetary gravity dominates
over solar tides4). The capture of the moons is then made
permanent by dissipative energy loss (for example, gas drag3) or
planetary growth2. But the observed distributions of orbital
inclinations, which now include numerous newly discovered
moons5–8, cannot be explained using current models. Here we
show that irregular satellites are captured in a thin spatial region
where orbits are chaotic9, and that the resulting orbit is either
prograde or retrograde depending on the initial energy. Dissipation
then switches these long-lived chaotic orbits10 into nearby
regular (non-chaotic) zones from which escape is impossible. The
chaotic layer therefore dictates the final inclinations of the
captured moons. We confirm this with three-dimensional
Monte Carlo simulations that include nebular drag3,4,11, and
find good agreement with the observed inclination distributions
of irregular moons at Jupiter7 and Saturn8. In particular, Saturn
has more prograde irregular moons than Jupiter, which we can
explain as a result of the chaotic prograde progenitors being
more efficiently swept away from Jupiter by its galilean moons.