accretion
In general, a process of growth by accumulation and adhesion.
Accretion disk
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An accretion disk is a structure that is created when matter falls into a gravitational source, like a wormhole.
Accretion Disk :
The center of active galaxies is the site of a wide range of activity apparently powered by the black hole. X-rays and gamma-rays are emitted from the area, and rapidly moving gas clouds can be observed there.
Accretion disks arise when material (usually gas) is being transferred from one celestial object to another. "accretion" means collecting of additional material.
An accretion disk is a disk of matter which forms around an object to which it is gravitationaly attracted. The reason the matter forms a disk is that it's angular momentum prevents it from falling directly onto the object.
Accretion Basics
By default, accretion power is the only way to generate AGN luminosities in the required small volumes for interestingly long times. A fiducial value for the expected maximum luminosity from accretion is the Eddington limit.
"The Keck measurements give us a uniquely high-resolution look at the innermost regions of the active nucleus, and the UKIRT images are very powerful in disentangling the contributions of the host galaxy and the accretion disc in the interferometry ...
Accretion - The growth in the mass of a body by the infall of matter gravitationally attracted to the body
Accretion Disk - A disk of gas and dust spiraling inward toward a star or toward the nucleus of a galaxy ...
accretion: The sticking together of solid particles to produce a larger particle.
accretion disk: The whirling disk of gas that forms around a compact object such as a white dwarf, neutron star, or black hole as matter is drawn in.
Accretion Disk: A disk of gas that accumulates around a center of gravitational attraction, such as a white dwarf, a neutron star, or a black hole.
accretion disk Flat disk of matter spiraling down onto the surface of a neutron star or black hole. Often, the matter originated on the surface of a companion star in a binary system.
Accretion
process of particles sticking together to form larger bodies; for example, solar nebular dust accreted to form chondrules, and planetesimals accreted to form planets.
Accretion: The growth of planets from smaller objects by impact, one impact at a time. After formation, planets are said to have "accreted" from small objects.
accretion
The process of growth of an object due to the gradual accumulation of material.
accretion disk
a disk surrounding a black hole or star in which matter gravitationally falls onto the central object
achromatic lens ...
ACCRETION DISK
An accretion disk is a flat disk of gas and dust in space that surrounds a newborn star, black hole, or other enormous object that is growing by attracting matter to it with its gravitational field.
...
ACCRETIONARY LAPILLI - Pellets that form by accretion of fine ash around condensing water droplets or solid particles; particularly common in steam-rich volcanic eruptive columns, ...
Accretion
(a) Collection of material together, generally to form a single body.
Accretion disks and gas jets
Most accretion disks and gas jets are not clear proof that a stellar-mass black hole is present, because other massive, ...
Accretion- accumulation of dust and gas into larger bodies such as stars, planets, and moons
Accretion disk- a disk of hot, glowing matter spiraling into a black hole ...
4) Accretion disk in a binary system
Gas flowing from one star falls toward its compact companion into an orbit around it.
The Accretion theory
This assumes that the Sun passed through a dense interstellar cloud and emerged surrounded by a dusty, gaseous envelope. It thus separates the formation of the Sun from that of the planets thus losing problem 1.
[edit] Accretion disk
A Chandra X-ray spectrum of Cygnus X-1 showing a characteristic peak near 6.
accretion Accumulation of dust and gas into larger bodies. albedo Reflectivity of an object; ratio of reflected light to incident light.
Accretion Disk
A relatively flat, rapidly rotating disk of gas surrounding a black hole, a newborn star, or any massive object that attracts and swallows matter.
Accretion in outer space tends to take place in a disk-like structure that surrounds the "accreting" object. Does this not remind you of the Solar System?
Accretion of smaller particles, and disaggregation due to tidal forces.
DIAGRAM OF SATURN'S RING SYSTEM
Saturn's moons and rings shown approximately to scale.
accretion disk - (n.)
A rotating disk of gas surrounding a compact object (such as a neutron star or black hole), formed by material falling inward.
albedo - (n.) ...
accretion disk
The whirling disk of gas that form around a compact object such as a white dwarf, neutron star or black hole as matter is drawn in.
active galactic nuclei (AGN) ...
accretion disk A disk of gas and dust that can accumulate around a center of gravitational attraction, such as a normal star, a white dwarf, neutron star, or black hole. As the gas spirals in due to friction, it becomes hot and emits radiation.
Accretion (astrophysics)
In astrophysics, the term accretion is used for at least two distinct processes.The first and most common is the growth of a massive object by gravity attracting more matter, typically gaseous matter in an accretion disc..
Accretion (finance)Accretion (geology)Accretion (science)
AccringtonAccrington (UK Parliament constituency)Accrington F.C.
Accrington PalsAccrington railway stationAccrington Stanley F.C.
Some accretion models of the solar system suggest that an early cometary bombardment of the Earth may have played a major role in the formation of the atmosphere and the oceans.
The cold accretion hypothesis holds that the Earth is made up entirely of cold carbonaceous chondrite material.
The core accretion model describes fails to
explain how the largest gas giants could have
formed quickly from Sol's protoplanetary disk.
However, accretion disks, jets, and orbiting objects are found not only around black holes, but also around other objects such as neutron stars; ...
However, this accretion process is not smooth, and sudden increases or decreases in the rate of accretion onto the protostar can occur. The effect of a sudden increase in the accretion rate is to produce 'bullets' of denser material in the jets.
solar system accretion (in solar system (astronomy): Differentiation into inner and outer planets; in meteorite (astronomy) )
contribution by ...
In the binary accretion model, the Moon was created out of the same cloud of material forming the Earth. The giant impact model, which is more popular, suggests when the Earth was young, a Mars-sized object hit the Earth.
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70. Co-Accretion Hypothesis
The theory that the moon and the earth formed together.
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71. Cocoon
The cloud of gas and dust around a contracting protostar that conceals it at visible wavelengths.
Continued growth by accretion leads to larger and larger objects. The energies released during accretionary impacts would be sufficient to cause vaporization and extensive melting, ...
protoplanet (NASA Thesaurus) Transition objects formed during primeval cloud condensation into stellar systems (stars, planets, etc.) which form the nucleus of planetary accretion. Used for planetesimals.
An accretion disk forms around the black hole. This would be much larger in size than the black hole and would be very hot and dense near the center - producing UV light and x-rays in most cases or even some gamma-rays.
furthermore suggest that FR-I sources are produced when the accretion rate onto the central black hole is low, and the black hole has relatively less angular momentum; ...
The moon probably formed by the cold accretion of small particles about 4.6 billion years ago at the same time that the rest of the solar system formed; thus, it is now believed that the moon was never in an entirely molten state.
Normally such X rays are produced by an "accretion disk", a dense, hot disk of gas that forms as the gas from a normal star spirals into a compact object.
There were three principal theories: co-accretion which asserted that the Moon and the Earth formed at the same time from the Solar Nebula; fission which asserted that the Moon split off of the Earth; ...
Speca (an acronym for Spiral-host Episodic radio galaxy tracing Cluster Accretion) first came to Ananda's attention in an image that combined data from the visible-light Sloan Digital Sky Survey and the FIRST survey done with the National Science ...
The matter spirals toward the black hole in an accretion disc. This accretion disc will emit X-rays. Such X-ray sources have been detected and some show evidence that the object accreting the matter is so massive that it must be a Black Hole.
This material forms a disk orbiting around the compact star known as an accretion disk. Gas in an accretion disk can become very hot and glow in visible, UV and X-ray light.
This material often forms an accretion disk. Similar luminous accretion disks can also form around white dwarfs and neutron stars, but in these the infalling gas releases additional energy as it slams against the high-density surface with high speed.
A black hole's gravity can sometimes be strong enough to pull off the outer gases of the star and grow a disk around itself called the accretion disk.
Artist's impression of accretion from a giant onto a white dwarf. Such a process is thought to be responsible for Type Ia supernovae.
6 billion years ago through a process called accretion. In the solar nebula that was left over after the formation of the Sun, all of the planets began to accrete mass. It all began with one larger body slowly impacting smaller bodies over and over.
Building Blocks of Planets (Accretion) (PDF, 225 KB)
Changes Inside Planets (Differentiation and Break Up)
Looking Inside Planets (Modeling Planet Interiors)
Impact Craters: Holes in the Ground ...
Exploration of Neptune's rings and the planet's magnetosphere, which are something like the Sun's nebula and the accretion disks seen around other stars.
The proposal.
Jets appear to originate in the vicinity of an extremely dense object, such as a black hole, pulsar, or protostar, with a surrounding accretion disk. These jets are thought to be perpendicular to the plane of the accretion disk.
The most common use of the word disk in astronomy is in describing round objects like the moon or planets. There is also the accretion disk which formed the solar system.
It is a region where the planet-building process was stopped in before any large objects were formed; there are only primitive remnants from the early accretion disk of the solar system, 4.5 billion years ago.
Because this lies inside the Roche limit, these moons could not have formed by accretion in their present location. They must have formed elsewhere before coming to their present orbits, though we are not certain where.
 See also: Energy, Mass, Time, Light, Solar
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