Short answers, pulled from the story.
10199 Chariklo is a ringed centaur and asteroid orbiting the Sun between Saturn and Uranus, with an average orbital distance of 15.7 astronomical units and an orbital period of 62.5 years. It is the largest known centaur, with a diameter of about 250 km. It was discovered on the 15th of February 1997 by the University of Arizona's Spacewatch project at Kitt Peak National Observatory.
Chariklo's rings were discovered on the 3rd of June 2013 during a stellar occultation, when astronomers observed Chariklo passing in front of a star and detected dips in the starlight caused by two narrow rings. Chariklo was the first minor planet confirmed to have a ring system.
The two rings are informally nicknamed Oiapoque (the inner ring, at a radius of 385.9 km) and Chuí (the outer ring, at 399.8 km), after the rivers forming Brazil's northern and southern coastal borders respectively. A formal request to the International Astronomical Union for official names has not yet been submitted.
Chariklo's surface is composed of water ice, silicate minerals, amorphous carbon, and complex organic compounds called tholins. James Webb Space Telescope observations in 2022 showed the water ice is in crystalline form, which is unusual because crystalline ice breaks down quickly under space radiation.
James V. Scotti made the discovery observations on the 15th of February 1997 using the Spacewatch 0.9-meter telescope at Kitt Peak National Observatory in Arizona. Chariklo was officially named on the 28th of September 1999 after Chariclo, the nymph from Greek mythology who was the wife of Chiron.
A mission concept called Camilla was published in June 2018, proposing a robotic flyby of Chariklo that would release a 100-kilogram tungsten impactor to excavate a crater about 10 meters deep for compositional analysis. The proposed launch date was September 2026, but the mission has not been formally submitted for NASA New Frontiers program funding.