protoplanetardisk

A protoplanetary disk is a rotating circumstellar disk of dense gas and dust surrounding a young newly formed star, a T Tauri star, or Herbig Ae/Be star. It is the region where planets, moons, asteroids, and other small Solar System bodies may form. The material in the disk gradually accretes onto the central star, or may coalesce to form planets and other bodies. Protoplanetary disks are thought to be the birthplace of planets and are a common feature of young stellar objects. They are typically several hundred astronomical units in diameter and are composed primarily of gas, with a smaller amount of dust particles. The disk material is in a state of Keplerian motion, orbiting the central star due to its gravitational influence. The temperature and density of the disk decrease with increasing distance from the central star. Protoplanetary disks are believed to dissipate over time, either through accretion onto the central star, or through other processes such as photoevaporation or planet formation. The study of protoplanetary disks is an active area of research in astronomy, as they provide valuable insights into the formation and evolution of planetary systems.