Moons ejected from orbits around gas giant exoplanets could explain several astronomical secrets, suggests an international team of astronomers.
Researchers led by Mario Sucerquia of the Universidad de Antioquia in Colombia and Jaime Alvarado-Montes of the Australian Macquarie University modeled the probable behavior of giant exo-mons expected to form massive planets ̵
About 50 percent of these ejected moons would survive both immediate expulsion and any subsequent collision with the planet or star, ending up as quasi-planets moving around the host star, but in eccentric "Pluto-like" orbits.
These rogue moons – referred to as "Ploonets" by Sucerquia, Alvarado-Montes and colleagues – could possibly explain several puzzling phenomena, not least because astronomers have so far confirmed the existence of at least 4098 exoplanets but not a single exomoon.
Most of the previously discovered planets are of the Hot Jupiter type, a fact that mainly reflects the limitations of current detection technology. Previous research suggests that at least some of these should be orbited by large moons.
The researchers write their absence in an article that could soon be published in the journal Monthly Notices of the Royal Astronomical Society . This can be explained by a scenario in which the moon is due to the angular momentum between the escapes both bodies of gravity of his parents.
"These moons would become planetary embryos or even full-fledged planets with highly eccentric orbits," explains Alvarado-Montes.
While researchers admit that ploonets remain hypothetical, their existence would provide a possible explanation for several of the more challenging results achieved with NASA's now retired Kepler Space Telescope.
These include the confusing dips in the light curves that emanate from a star formally known as KIC-8462852.
"It's better known as Tabby Star," says Alvarado-Montes, "and the strange changes in its light intensity you've been watching for years, but still not understood." Ploonets might be the answer. "
You could also explain obvious evidence of cannibalism between some stars or the existence of "exokomets" around other stars.
Ploonets could therefore be an important piece of the planetary puzzle, but their existence is not yet proven.
Sucerquia, Alvarado-Montes and colleagues admit that even if they exist, they may deteriorate too quickly to ever be observed.
write: "The timescales are big enough, we could have real chances to track them down in the near and medium term."
The publication "Ploonets: Education, Evolution and Recognizability of tidally detached exomoons" is currently available on arXiv, the preprint library of Cornell University in the US.
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Mario Sucerquia et al. Ploonets: formation, development and recognition of tidally detached exomoons. arXiv: 1906.11400v1 [astro-ph.EP]: arxiv.org/abs/1906.11400
Ploonets: Exiled Moons Explain Astronomical Secrets (2019, July 12)
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