Free Astronomy Magazine

SMALL BODIES biting Chariklo. This is not the first time that ring systems around solar system bodies are discovered through stellar occultations, as it had already happened in 1977 with Uranus and in 1984 with Neptune, but it is certainly the first time that rings are discovered around an asteroid. Chariklo – for however small – becomes therefore the fifth plane- tary body to have a system of rings after the I n the illustration to the right and in the video below, a spectacular reconstruction of the Chari- klo system, with a transit between the two rings discovered by the Braga-Ribas’ team. We also note the presence of a small satellite that with its action provides the gravitational confinement that gives to the rings their well-defined shape. [ESO/L. Calçada/M. Kornmesser/N. Risinger] bedo (and then actually confirmed by the occultation observation), astronomers also wanted to use the event to understand the causes of the unusual spectrophotometric behaviour to which Chariklo had been sub- jected between 1997 and 2008, when its brightness had been gradually dimming by nearly a factor of 2 and from its spectrum had disappeared the absorption band at 2 μ m of the water ice. Then, from 2008 to 2013 its brightness started to pick up again to almost the level of '97 and the presence of water ice became detectable again. Mys- teries that the predicted occultation would have probably allowed to unravel. Of all the telescopes dedicated to the obser- vation of the phenomenon, 3 sited in Chile recorded the event in line with predictions and 7 in total recorded a dozen unexpected events in the form of secondary interrup- tions of the luminous flux of the star. Due to the high acquisition rate of images by the Lucky Imager camera of the Danish tele- scope at ESO, two secondary events (one preceding and the other following the main one) were each resolved into two sub- events, which the team of researchers led by Braga-Ribas interpreted as a pair of rings or-