Akrecja

Akrecja is a term used in Polish science to describe the process by which an object increases its mass by gradually incorporating material from its surroundings. The mechanism can be gravitational, hydrodynamic, chemical, or mechanical, and it often operates over extended timescales.

In astronomy and astrophysics, accretion refers to growth of a celestial body by capturing gas, dust, or other matter from a surrounding medium. Accretion disks form around young stars, white dwarfs, neutron stars, and black holes, where material spirals inward and releases energy as radiation. In planet formation, the core accretion model describes a protoplanet growing by accumulating solid bodies and, if enough mass is present, a gaseous envelope. In binary systems, accretion can occur from one star to its companion, influencing luminosity and evolution.

In geology and planetary science, accretion denotes the buildup of sediments, rocks, or planetary material on surfaces, often through collisions or adhesion in the early solar system. Subduction zones can form accretionary prisms as sediments are scraped from a subducting plate and accreted to the overriding plate. The broader concept also covers planetary accretion—the coalescence of dust and planetesimals into larger bodies during planet formation.

In materials science, accretion describes the growth of deposits on surfaces, such as mineral scales, corrosion products, or crystalline layers that form by progressive attachment of atoms or molecules.

Etymology: from Latin accretio, via French accrétion; in Polish usage it is a general term for gradual growth by attachment.