Accretion lines, pronounced /əˈkriːʃən laɪnz/, refer to the lines of material that flow from one astronomical object to another, such as from a star to a black hole. The spelling of the word "accretion" is derived from the Latin word "accretio" meaning growth or increase. The pronunciation of "accretion lines" involves emphasis on the first syllable, with the second syllable pronounced with a long "e" sound. The pronunciation of "lines" involves an "ai" diphthong sound followed by a voiced "n" consonant.
Accretion lines refer to the luminous hot gas that is gravitationally pulled towards a celestial object, such as a star, a black hole, or a neutron star, through accretion.
Accretion is the process by which matter accumulates onto an astronomical object due to its gravitational attraction. Accretion lines are the regions where this matter, often in the form of a gas or plasma, is being pulled towards the massive object. As the gas spirals closer and closer towards the object, it forms these lines, resembling thin, glowing filaments or trails.
These lines are the result of the gravitational forces creating a powerful magnetic field around the object. The magnetic field forces the gas to follow specific paths, often along the magnetic field lines, as it spirals towards the object. During this process, the gas heats up due to friction and pressure, giving rise to the luminosity observed in the accretion lines.
Accretion lines are commonly observed in various astrophysical phenomena, such as in binary star systems where one star transfers mass onto another, in active galactic nuclei where massive black holes accumulate matter, or in the formation of protostars. Studying these accretion lines provides valuable insights into the dynamics, energetics, and evolutionary processes of celestial objects.
Lines seen in microscopical sections of the enamel, marking successive layers of added material.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The term "accretion lines" is derived from the word "accretion" and the word "lines".
The word "accretion" comes from the Latin word "accretio", which means "growth" or "increase". In the context of astrophysics, accretion refers to the process by which matter accumulates or gathers together through gravitational attraction. In particular, it refers to the accumulation of matter onto a celestial object, such as a star or a black hole.
The term "lines" refers to the phenomenon of spectral lines that are observed in the electromagnetic spectrum, specifically in the context of spectroscopy. Spectral lines are the specific wavelengths of light that are emitted or absorbed by atoms or molecules when they undergo transitions between energy levels. These lines can provide important information about the composition, temperature, and other properties of celestial objects.