accretion


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accretion

1. Botany the growing together of normally separate plant or animal parts
2. Pathol
a. abnormal union or growing together of parts; adhesion
b. a mass of foreign matter collected in a cavity
3. Law an increase in the share of a beneficiary in an estate, as when a co-beneficiary fails to take his share
4. Astronomy the process in which matter under the influence of gravity is attracted to and increases the mass of a celestial body. The matter usually forms an accretion disc around the accreting object
5. Geology the process in which a continent is enlarged by the tectonic movement and deformation of the earth's crust

accretion

(aggregation) The increase in mass of a body by the addition of smaller bodies that collide and stick to it. The relative velocity of any two colliding bodies must be low enough for them to coalesce on impact rather than fly apart. Once a large enough body forms, its gravitational attraction accelerates the accretion process. Accreting objects in the Universe are numerous and diverse. They include protoplanets, protostars, black holes, and X-ray binaries. The accretion process is thought to occur generally in the form of a disk. Accretion is now assumed to have had an important role in the formation of the planets from swarms of dust grains. In the outer Solar System the grains were like dirty snowflakes and thus accretion was accelerated. See Solar System, origin.

accretion

[ə′krē·shən]
(astronomy)
A process in which a star gathers molecules of interstellar gas to itself by gravitational attraction.
(civil engineering)
Artificial buildup of land due to the construction of a groin, breakwater, dam, or beach fill.
(geology)
Gradual buildup of land on a shore due to wave action, tides, currents, airborne material, or alluvial deposits.
The process whereby stones or other inorganic masses add to their bulk by adding particles to their surfaces. Also known as aggradation.
(meteorology)
The growth of a precipitation particle by the collision of a frozen particle (ice crystal or snowflake) with a supercooled liquid droplet which freezes upon contact.
References in periodicals archive ?
"Moreover, the detection of a thin disc, which extends below 100 rg in an L/LEdd a1/4 10a4 system, contradicts the current view of the accretion flow configuration at extremely low accretion rates."
The contribution of this cooler gas to the accretion flow onto the black hole was previously unknown.
Australia and Africa are also both experiencing more erosion than growth, while Asia has experienced the largest accretion, partially due to human-led developments and land reclamations in countries such as China, Singapore, Bahrain and the UAE.
The decrease was principally driven by lower accretion income of $1.9 million, compared to $3.7 million in the first quarter of 2018.
The City Government opposed the application for land registration, stating that it needed the property for its flood control program; that the property was within the legal easement of 20 meters from the river bank; and that assuming that the property was not covered by the legal easement, title to the property could not be registered in favor of the applicants for the reason that the property was an orchard that had dried up and had not resulted from accretion.
He expressed optimism that with the determination of the Bank and the cooperation of the fiscal authorities, the external reserves will continue to enjoy more accretion in the course of 2018.
Yet the 2 million-year-old object is growing from an accretion disk, as stars do.
The net interest margin, exclusive of the impact of purchase accounting accretion equaled 4.50%, in the first quarter of 2017 compared to 4.28% in the first quarter of 2016 and 4.33% in the fourth quarter of 2016.
In addition, research on the influence on the bundle space and the initial ice accretion angle of the crescent iced 4-bundled conductors is still rare.
For an accretion to occur, there must be sufficient continuity of operations to justify applying the existing union contract, considering factors such as whether operations are "substantially the same" and whether transferred employees from the old facility constitute a substantial percentage of the new plant's employee complement (usually at least 40 percent).
The USD117,000 net income reflects a deduction of USD192,000 in Troubled Asset Relief Programme (TARP) preferred stock dividends and discount accretion. The latest earnings compares to net income of USD518,000, or USD0.24 per share, basic and diluted, for the quarter ended March 31, 2014, also after deduction of TARP dividends and discount accretion.
You see, black holes have normally been indicated by their accretion disc - a collection of primarily stellar gases and space dust that orbit around it, and from where this matter is sucked into the black hole itself.