In other star techniques, some moons may escape their planets and begin orbiting their stars instead, new simulations suggest. Scientists have interpreted such liberated worlds “ploonets,” and said that modern telescopes might be able to find the wayward objects.
Astronomers think that exomoons moons orbiting planets that orbit stars other than the sun must be common, however efforts to find them have turned up empty to date. Astrophysicist Sucerquia of the University of Antioquia in Medellín, Colombia, and co-workers simulated what would occur to these moons if they orbited hot Jupiters, gas giants that lie scorchingly near their stars. Few astronomers think that hot Jupiters weren’t born so close, however instead migrated toward their star from a more distant orbit.
Because the gas giant migrates, the combined gravitational forces of the planet and the star could inject extra power into the moon’s orbit, pushing the moon farther and farther from its planet until ultimately, it escapes, the researchers report June 29 at arXiv.org.
“This process should occur in every planetary system composed of a giant planet in a close-in orbit,” Sucerquia says. “So ploonets should be very frequent.”
The study is an excellent first step for thinking about what would occur to exomoons in actual planetary methods, says planetary astrophysicist Natalie Hinkel of the Southwest Research Institute in San Antonio, who wasn’t involved within the new work. “Nobody’s seemed on the problem quite like this,” she says. “It provides to the layers of how difficult these systems are.”
Plus, ploonet is “a wonderful name,” Hinkel says. “Normally I form of eye-roll at these made-up names, but this one is a keeper.”