Protoplanetary disk

Gas and dust surrounding a newly formed star

A protoplanetary disk is a rotating circumstellar disc of dense gas and dust surrounding a young newly formed star, a T Tauri star, or Herbig Ae/Be star. The protoplanetary disk may not be considered an accretion disk; while the two are similar, an accretion disk is hotter and spins much faster, accreting matter onto a central body; it is also found on black holes, not only stars. This process should not be confused with the accretion process thought to build up the planets themselves.

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