protoplanetarisen

A protoplanetary disk is a torus-shaped cloud of gas and dust surrounding a young, newly formed star. These disks are the birthplaces of planets, forming through the accretion of material over millions of years. The process begins with a collapsing cloud of gas and dust in space, which, under its own gravity, forms a protostar at its center. As the protostar grows, conservation of angular momentum causes the surrounding material to flatten into a disk.

Within this protoplanetary disk, the dust grains collide and stick together, gradually growing larger. These clumps can eventually form planetesimals, which are kilometer-sized objects. Planetesimals continue to collide and accrete, eventually forming protoplanets, which are the precursors to full-fledged planets. The composition of the planets that form depends on their location within the disk. Closer to the star, temperatures are higher, allowing only rocky and metallic materials to condense, forming terrestrial planets. Further out, in the colder regions, volatile compounds like water, methane, and ammonia can freeze, leading to the formation of gas giants and ice giants.

The protoplanetary disk eventually dissipates, either by being incorporated into the forming planets, blown away by stellar winds, or dispersed by gravitational interactions. The study of protoplanetary disks is crucial for understanding planet formation and the diversity of planetary systems observed throughout the galaxy. Telescopes like the Atacama Large Millimeter/submillimeter Array (ALMA) have provided unprecedented views of these disks, revealing intricate structures and providing direct evidence of ongoing planet formation.