This simple question – asked about the four year old son of the Carnegie Juna Kollmeier – started everything. Not long after this initial consultation, Kollmeier was coordinating a program at the Kavli Institute for Theoretical Physics (KITP) in the Milky Way, while his classmate Sean Raymond, from the University of Bordeaux, attended a parallel program of KITP on Planet Dynamics similar to Earth. After talking about this very simple question in a seminar, the two joined forces to solve & # 39; l. Their findings are the basis of a document published in Monthly announcements of the Royal Astronomical Society.
The duo started an Internet demonstration at the end of last year when he published a draft of his article examining the possibility that moons orbiting other moons on a pre-press server for manuscripts of physics and astronomy .
The online conversation is obsessed with the best term to describe these phenomena with options such as moon-ammunition and mini-moons that are thrown into the mix. But the nomenclature was not the point of the investigation of Kollmeier and Raymond (although they had preference for sub-areas). Rather, they proposed defining the physical parameters for moons that could be openly stable for other smaller moons.
"The planets orbit the stars and planets of the orbits of the moons, so it was natural to ask if the smaller moons could orbit the larger ones," explained Raymond.
His calculations show that only the great moons in wide orbits of his host planets could hold submax. The tide forces of both the planet and the moon act to destabilize the orbits of the subarea orbiting smaller moons or moons closer to the host planet.
They found that four moons in our own solar system are theoretically able to accommodate their own satellite submersions. The moon of Jupiter Callisto, the moons of Saturn Titan and Iapetus, and the Moon's own Earth, is adapted to the invoice of a satellite that could lodge its own satellite, although none of them have been found to date. However, they add that new calculations are needed to deal with possible sources of underwater instability, such as the non-uniform mass concentration in the crust of our Moon.
"The lack of known sub-areas of our Solar System, even orbiting the moons that could support theoretically these objects, can offer us clues about how our own planets and neighbors were formed, about which there are still many outstanding questions" , explained Kollmeier.
The moons that orbit Saturn and Jupiter are believed to have been born from the gas and dust disc that surround the giant gas planets in the later stages of their formation. Our own Moon, on the other hand, is believed to have originated after a giant impact between the young Earth and a sea-sized body. The lack of stable sub-areas could help scientists better understand the different forces that make up the satellites that we see.
Kollmeier added: "and, of course, this could inform the ongoing efforts to understand how planetary systems evolve elsewhere and how our own solar system adjusts to the thousands of other discoveries by the planet hunting missions ".
For example, the recently discovered exotone that orbits the Jupiter Size Kepler 1625b is the appropriate mass and the distance of its host to support a sublime, found by Kollmeier and Raymond. Although the inferred incline of its orbit could make it difficult for such an object to remain stable. However, the detection of a sub-menu around an exotic would be very difficult.
Given the enthusiasm that surrounds the potentially habitable exoplanet searches, Kollmeier and Raymond calculated that the best scenario for life in large sub-areas is around massive stars. Although they are extremely common, small red dwarf stars are so weak and their habitable areas so close that the tide forces are very strong and the floods (and often even the same moons) are unstable.
Finally, the authors point out that an artificial submunction can be stable and, therefore, serve as a temporary or advanced capsule. In a stable orbit to the Moon, such as the lunar entrance door proposed by NASA, a submarine would keep the treasures of humanity safe for posterity long after the Earth became inadequate for life. Kollmeier and Raymond agree that there is much more work to do (and fun) to understand the submenu (or lack of it) as a rocky record of the history of moon-planet systems.
Sean Raymond maintains a scientific blog (planetplanet.net) where more details and illustrations can be found (including a poem he wrote about the article).
This research was supported by a grant from the Agence Nationale pour la Recherche, the virtual leadership team of the Planetary Planetary of the Astrobiology Institute of NASA and the National Science Foundation.