AsianScientist (Sep. 26, 2016) – It turns out that the existence of rings around minor planets known as centaurs are more common than previously thought. The Japanese team’s findings were published in Astrophysical Journal Letters.
Centaurs are minor planets that orbit between Jupiter and Neptune, their current or past orbits crossing those of the giant planets. Until recently, it was thought that the four giants such as Saturn and Jupiter were the only ringed celestial bodies within our solar system.
In 2014, however, observations of stellar occultation—an event that occurs when light from a star is blocked from the observer by a celestial body—by multiple telescopes revealed that rings exist around the centaur Chariklo. Soon after this, scientists discovered that rings likely exist around another centaur, Chiron, but the origin of the rings around these minor planets remained a mystery.
To investigate the origin of the rings, Professor Ryuki Hyodo of Kobe University and his team began by estimating the probability that these centaurs passed close enough to the giant planets to be destroyed by their tidal pull. Their results showed that approximately ten percent of centaurs would experience that level of close encounter.
Next, they used computer simulations to investigate the disruption caused by tidal pull when the centaurs passed close by the giant planets. The outcome of such encounters was found to vary depending on parameters such as the initial spin of the passing centaur, the size of its core, and the distance of its closest approach to a giant planet. They found that if the passing centaur fulfils certain physical requirements, fragments of the partially-destroyed centaur will often spread out around the largest remnant body in a disc shape, from which rings are expected to form.
The results of their simulations suggest that the existence of rings around centaurs would be much more common than previously thought. It is highly likely that other centaurs with rings or small moons exist, awaiting discovery by future observations, the authors say.
The article can be found at: Hyodo et al. (2016) Formation of Centaurs’ Rings through Their Partial Tidal Disruption during Planetary Encounters.
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Source: Kobe University.
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