What is "carbon planet"

n. (context astronomy English) A theoretical type of terrestrial planet that could form if protoplanetary discs are carbon-rich and oxygen-poor.

A carbon planet is a theoretical type of planet that contains more carbon than 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 C/O 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. The theory is now built on reasonable scientific ideas and has gained support. Different planetary systems have different carbon-to-oxygen ratios, with the Solar System's terrestrial planets are closer to being "oxygen planets". The exoplanet PSR J1719-1438 b, discovered on August 25, 2011, as well as the planet 55 Cancri e, could be such planets.