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The Fate of Exomoons when Planets Scatter
Planet interactions are thought to be common as solar systems are first forming and settling down. A new study suggests that these close encounters could have a significant impact on the moons of giant exoplanets — and they may generate a large population of free-floating exomoons.
[...] Led by Yu-Cian Hong (Cornell University), a team of scientists has now explored the fate of exomoons in planet–planet scattering situations using a suite of N-body numerical simulations. Hong and collaborators find that the vast majority — roughly 80 to 90% — of exomoons around giant planets are destabilized during scattering and don't survive in their original place in the solar system. Fates of these destabilized exomoons include:
- moon collision with the star or a planet,
- moon capture by the perturbing planet,
- moon ejection from the solar system,
- ejection of the entire planet–moon system from the solar system, and
- moon perturbation onto a new heliocentric orbit as a "planet".
[...] An intriguing consequence of Hong and collaborators' results is the prediction of a population of free-floating exomoons that were ejected from solar systems during planet–planet scattering and now wander through the universe alone. According to the authors' models, there may be as many of these free-floating exomoons as there are stars in the universe!
There are no confirmed exomoons yet. Rogue planets may have their own satellites as well.
Innocent Bystanders: Orbital Dynamics of Exomoons During Planet–Planet Scattering (DOI: 10.3847/1538-4357/aaa0db) (DX)
(Score: 2) by ese002 on Wednesday March 14 2018, @07:09PM (1 child)
It still pretty much empty. These objects are very very sparsely distributed. What makes rogue moons and planets interesting is that you may encounter a sizable natural object that isn't emitting any light. In system, asteroids, planets, dwarf planets, and moons are illuminated by the sun. But in the vast spaces between stars, there is no significant light to reflect. The odds of encountering one is remote, but if you do, you won't get much warning.
(Score: 2) by PinkyGigglebrain on Thursday March 15 2018, @08:01PM
I was mostly commenting on how Humanities view of interstellar space has changed over the years. I know that the space really is mostly empty, and the odds that you will encounter something bigger that a dust grain is really, really, really, small, but it is non-zero and if precautions are not taken there will be a collision someday, and it wouldn't take much to ruin everyone's day..
I expect that before Humans actually launch a ship fast enough for it to matter that they won't have years or decades to make course corrections, they would have done something to detect the junk in the path of a fast star ship. Probably be quite the array of imaging devices and probably some kind of radar, I could see most of the ship's width might just be the dish antennae needed to detect the return signal.
I just had an interesting thought that the first non Human signal SETI picks up might be the "ping" from a star ship's navigation radar. I wonder what the blue shift of a radar pulse would be for ship moving at a good % of c? It might push the frequency outside something Earth's SETI program can currently pickup. The ship also wouldn't need to ping very often too.
Well, Humanity has plenty of time to figure all that out, if they don't screw things up and wipe out their civilization first.
"Beware those who would deny you Knowledge, For in their hearts they dream themselves your Master."