| Abstract from DBPedia | A carbon planet is a theoretical type of planet that contains more carbon than oxygen. Carbon is the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. Marc Kuchner and Sara Seager coined the term "carbon planet" in 2005 and investigated such planets following the suggestion of Katharina Lodders that Jupiter formed from a carbon-rich core.Prior investigations of planets with high carbon-to-oxygen ratios include Fegley & Cameron 1987. Carbon planets could form if protoplanetary discs are carbon-rich and oxygen-poor. They would develop differently from Earth, Mars, and Venus, which are composed mostly of silicon–oxygen compounds. Different planetary systems have different carbon-to-oxygen ratios, with the Solar System's terrestrial planets closer to being "oxygen planets" with C/O molar ratio of 0.55. In 2020, survey of the 249 nearby solar analog stars found 12% of stars have C/O ratios above 0.65, making them candidates for the carbon-rich planetary systems. The exoplanet 55 Cancri e, orbiting a host star with C/O molar ratio of 0.78, is a possible example of a carbon planet.炭素惑星（英語: carbon planet）とは、アメリカの天体物理学者 Marc Kuchner が提唱した惑星の類型。炭素やその化合物を主な成分とする固体の天体である。英語では diamond planet（ダイヤモンド惑星）やcarbide planet（炭化物惑星）とも呼ばれる（ただし前者については惑星全体がダイヤモンドというわけではない）。2011年の時点では実際に確認された例はなく、理論上の存在である。 (Source: http://dbpedia.org/resource/Carbon_planet) |
