Solar analog (–0.21) for solar twin. 16 Cygni B is sometimes noted as twin, but is part of a triple star system and is very old for a solar twin at over 9 Gyr. Another way of defining solar twin is as a "habstar" — a star with qualities believed to be particularly hospitable to an Earth-like planet. Qualities considered include variability, mass, age, metallicity, and close companions. The requirement that the star remain on the main sequence for at least 3 Ga sets an upper limit of approximately 1.5 solar masses, corresponding to a hottest spectral type of F5 V. Such
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.