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Accretion Disk ○꠹｜Definition｜1st｜20260103011930-00-⌔
Accretion disk
An accretion disk is a structure (often a circumstellar disk) formed by diffuse material1 in orbital motion around a massive central body. The central body is most frequently a star. Friction, uneven irradiance, magnetohydrodynamic effects, and other forces induce instabilities causing orbiting material in the disk to spiral inward toward the central body. Gravitational and frictional forces compress and raise the temperature of the material, causing the emission of electromagnetic radiation. The frequency range of that radiation depends on the central object’s mass. Accretion disks of young stars and protostars radiate in the infrared; those around neutron stars and black holes in the X-ray part of the spectrum. The study of oscillation modes in accretion disks is referred to as diskoseismology.23
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In astrophysics, diffuse material refers to interstellar or intergalactic matter that is spread out and not concentrated in a specific location. This material can include gas, dust, and other particles that are not organized into distinct structures like stars or galaxies. ↩
Nowak, Michael A.; Wagoner, Robert V. (1991). “Diskoseismology: Probing accretion disks. I - Trapped adiabatic oscillations”. Astrophysical Journal. 378: 656–664. Bibcode:1991ApJ…378..656N. doi:10.1086/170465. ↩
Wagoner, Robert V. (2008). “Relativistic and Newtonian diskoseismology”. New Astronomy Reviews. 51 (10–12): 828–834. Bibcode:2008NewAR..51..828W. doi:10.1016/j.newar.2008.03.012. ↩
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