Planet consists mostly of planets the size of Neptune and smaller, down to smaller than Mercury. There are types of planets that do not exist in the Solar System: super-Earths and mini-Neptunes, which could be rocky like Earth or a mixture of volatiles and gas like Neptune—a radius of 1.75 times that of Earth is a possible dividing line between the two types of planet. There are hot Jupiters that orbit very close to their star and may evaporate to become chthonian planets, which are the leftover cores. Another possible type of planet is carbon planets, which form in systems with
Solar art prize Solar art prize The Solar art prize is an annual art exhibition hosted by the Royal Society of the Arts, South Australia. The prize was established by Pip Fletcher in 2010, and has consistently invited artists to respond to the subject of climate change. The event's recurring theme is "Caring for Our Planet". Artists are invited to submit new works for consideration, and various prizes are offered. Prizes include cash and sponsor offerings, including tens of thousands of dollars in credits to be redeemed on solar power system services and installations, which include solar panels, hot water systems and batteries.