Posted on January 24, 2019
"An artificial submunaire may be stable, serving as a time capsule or outpost for a technological civilization. In a stable orbit around the Moon ̵
Can a moon have moons? This simple question, posed by Carnegie Observatory's four-year-old son Juna Kollmeier, started it all. Not long after that first bedtime, astrophysicist Kollmeier coordinated a program at Kavli Institute for Theoretical Physics (KITP) on the Milky Way, while her former college classmate Sean Raymond from Université de Bordeaux participated in a parallel KITP program on dynamics Earth-like planet.
After discussing this very simple question in a seminar, the two joined together to solve it. Their findings form the basis of a paper published in Monthly Notices of the Royal Astronomical Society.
Moons of extraterrestrial planets – "Enriching living spaces for life enormously"
Faced with the excitement surrounding the search for potentially habitable exoplanets, Kollmeier and Raymond calculated that the best case for living on large submonsibles are the stars. Although very common, small red dwarf stars are so weak and their habitable zones so close that the tidal forces are very strong and the submunons (and often even the moons themselves) are unstable.
The duo launched late last year with an Internet firestorm published a draft of their article exploring the possibility of moons circulating other moons on a preprint server for manuscripts for physics and astronomy.
The online conversation was obsessed with the best term to describe such phenomena with options such as lunar moons and thrown mini-moons into the mix. However, the nomenclature was not the subject of investigations by Kollmeier and Raymond (though they have a preference for submonsibles). Rather, they wanted to define the physical parameters for moons that would be able to be stably circumnavigated by other, smaller moons.
"Planets orbiting stars and moons orbiting planets, it was natural to ask if smaller moons could orbit larger ones," Raymond explained.
Their starting point, reported Physics Today, was an analysis by Jason Barnes and David O'Brien on the stability of exomons near exoplanets in 2002. The main ingredient of the study consisted of tidal forces from both the star and the host planet that can conspire to effect A moon must be sufficiently massive and sufficiently far away from the host planet, Kollmeier and Raymond observed, that the predominant magnetism of a submoon is the moon, not the planet, and Kollmeier and Raymond have one Stability criterion derived Then it was applied to the solar system's largest moons and to the Kepler-1625b-I Exomoon candidate Neptune's Moons were the least hospitable. Only the largest, Triton, could accommodate a submoon, and only if its radius was less than 5 km. Surprisingly, Jupiter's Callisto, Saturn's Titan and Iapetus (pictured above) and the Earth's Moon could take sub-moons with a radius of 20 km or more. The most oncoming moon of all turned out to be Kepler-1625b-I (picture above on the page).
"Facing the Simple Explanation" – Kerpler Reports First Discovery of a Monster Moon Orbiting an Alien Planet
Their calculations show that only large moons in broad orbits of their host planets can accommodate submamoises. The tidal forces of both the planet and the moon destabilize the orbits of submobos orbiting smaller moons or moons closer to their host planet.
They found that four moons in our own solar system are theoretically able to record their own satellite submamoises. Jupiter's moon Callisto, Saturn's moons Titan and Iapetus, as well as Earth's own moon, all fit into the bill of a satellite that could record its own satellite, although no one has yet been found. However, they add that further calculations are needed to address possible sources of submoon instability, such as the uneven mass concentration in the lunar crust of our moon.
"The absence of known submoons in our solar system that orbits even moons Theoretically, one could support such objects and give us clues as to how our own and neighboring planets have formed, and many more questions remain," said Kollmeier.
It is believed that the moons orbiting Saturn and Jupiter emanate from the disk of gas and dust surrounding the gas giant planets in later stages of their formation.It is believed that our own moon after a huge collision between the The lack of stable submamoises could help scientists better understand the various forces that shaped the satellites.
Kollmeier added, "This, of course, could influence ongoing efforts, to understand how planetary systems evolve elsewhere and what our own solar system is like. The system fits Thousands of others discovered by planet hunt missions. "
For example, the newly discovered potential Exomoon orbiting Jupiter-Kepler 1625b found the right mass and distance from its host to support a Submoon, Kollmeier and Raymond. However, the derived inclination of its orbit might prove difficult make such an object stable. However, discovering a submono around an Exomoon would be very difficult.
The Daily Galaxy on Physics Today and Carnegie Observatory