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accretion and all
However, when accretion disc energy-production mechanisms were successfully modeled in the 1970s, the argument that quasars were too luminous became moot and today the cosmological distance of quasars is accepted by almost all researchers.
The calcareous – probably aragonitic – shells have a cover ( operculum ) and two curved supports known as helens, all of which grew by marginal accretion.
Accretion discs are an ubiquitous phenomenon in astrophysics ; active galactic nuclei, protoplanetary discs, and gamma ray bursts all involve accretion discs.
It is debatable whether all such systems are true AGN ( powered by accretion on to a supermassive black hole ).
For accreting black holes, all the energy released by accretion does not have to appear as outgoing luminosity, since energy can be lost through the event horizon, down the hole.
In this model ice giants — Uranus and Neptune — are failed cores that began gas accretion too late, when almost all gas had already disappeared.
These candidates are all members of X-ray binary systems in which the compact object draws matter from its partner via an accretion disk.
For example, in Alberta all common law right except accretion have been replaced by statutory rights and obligations.
Gowachin law is based upon the notion of a healthy disrespect for all laws ; the purpose of this notion is to avoid the stultifying accretion of a body of laws and precedents that bind Gowachin mechanically.
Globular clusters thought to be associated with the Canis Major Dwarf galaxy include NGC 1851, NGC 1904, NGC 2298 and NGC 2808, all of which are likely to be remnants of the galaxy's globular cluster system before its accretion, or swallowing, into the Milky Way.
He claimed fascism represented the ' autobiography of the nation ', an accretion of all the ills of Italian society.
:"... the church on this site was described early in the 18th century as being still venerated by local people although it had been abandoned at the Reformation in favour of a more central parish church ... ... from the sandy spit, which has formed between the mainland and the isle, gales have carried sand and this, together with the accretion of a graveyard in use until c. 1850, buried the church remains and all knowledge of its exact location had vanished from living memory ... At the occasion of the first Viking Congress in 1951 Dr W. Douglas Simpson suggested a search might prove rewarding and this was undertaken in 1955 by a party of my students under my direction.
The same process is expected to produce accretion disks around virtually all newly forming stars in the universe, some of which yield planets.
Active Galactic Nuclei, accretion disks, and supernovae all emit UV radiation strongly, and many chemical elements have strong absorption lines in the UV, so that UV absorption by the interstellar medium provides a powerful tool for studying its composition.

accretion and T
The protoplanetary disk is sometimes referred to as an accretion disk, because while the young T Tauri-like protostar is still contracting, gaseous material may still be falling onto it, accreting on its surface from the disk's inner edge.
This process competes against the stellar wind, which drives the gas out of the system, and accretion, which pulls material into the central T Tauri star.
However, when contacted by Scientific American, Dr Sion said that the term " soon " in the press announcement meant that " At the accretion rate we derived, the white dwarf in T Pyxidis will reach the Chandrasekhar Limit in ten million years.
The T Tauri wind, so named because this young star is currently in this stage, is a phase of stellar development between the accretion of material from the slowing rotating material of a solar nebula and the ignition of the hydrogen that has agglomerated into the protostar.
The current model associates the FU Orionis flare with abrupt mass transfer from an accretion disc onto a young, low mass T Tauri star.
* Steeghs, D., Harlaftis, E. T., and Horne, K. ( 1997 ) Spiral structure in the accretion disc of IP Pegasi, Monthly Notices of the Royal Astronomical Society, 290 ( 2 ): L28 – L32.

accretion and stars
The huge luminosity of quasars results from the accretion discs of central supermassive black holes, which can convert on the order of 10 % of the mass of an object into energy as compared to 0. 7 % for the p-p chain nuclear fusion process that dominates the energy production in sun-like stars.
In the past, it was thought that this radiation pressure might be substantial enough to halt accretion onto the massive protostar and prevent the formation of stars with masses more than a few tens of solar masses.
Because compact stars have high gravitational fields, the material falls with a high velocity towards the neutron star, usually colliding with other accreted material en route, forming an accretion disk.
Most X-ray bursters have irregular periods, which can be on the order of a few hours to many months, depending on factors such as the masses of the stars, the distance between the two stars, the rate of accretion, and the exact composition of the accreted material.
A planetary system and various minor objects such as asteroids, comets and debris, can form in a hierarchical process of accretion from the protoplanetary disks that surrounds newly created stars.
For accretion powered sources such as accreting neutron stars or cataclysmic variables ( accreting white dwarfs ), the limit may act to reduce or cut off the accretion flow, imposing an Eddington limit on accretion corresponding to that on luminosity.
The disk eventually disappears due to accretion onto the central star, planet formation, ejection by jets and photoevaporation by UV-radiation from the central star and nearby stars.
He defined several differing types of presolar grains ( STARDUST from red giant stars, SUNOCONs from supernovae, NEBCONs from nebular accretion, and NOVACONs from novae ), but his suggestions lay dormant for a decade until these grains were discovered within meteorites.
Add-ons also include extensive space objects such as red and blue supergiants, red and brown dwarfs, neutron stars, spinning pulsars, rotating black holes with accretion disks, protostars, star nursery nebula, supernova and planetary nebula, galactic redshifts, geological planetary displays ( e. g. 3-D interiors, topographic and bathymetric maps, ice age simulations ), planetary aurorae, rotating magnetic fields, animated solar flares and prominences, 3-D craters and mountains, and historic collision events.
The term planetar exists for those accretion masses that seem to fall between stars and planets.
The generally accepted difference is one of formation ; stars are said to have formed from the " top down "; out of the gases in a nebula as they underwent gravitational collapse, and thus would be composed almost entirely of hydrogen and helium, while planets are said to have formed from the " bottom up "; from the accretion of dust and gas in orbit around the young star, and thus should have cores of silicates or ices.
These pulsars are thought to be spun up by the accretion of material from binary companion stars, in a previous X-ray binary phase.
Because they are associated with the youngest stars, where accretion is particularly strong, infrared bow shocks are usually associated with more powerful jets than their optical HH cousins.
The high metallicity of Population I stars makes them more likely to possess planetary systems than the other two populations, since planets, particularly terrestrial planets, are thought to be formed by the accretion of metals.
Similar jets, though on a much smaller scale, can develop around the accretion disks of neutron stars and stellar black holes.
He has pursued a broad range of problems ranging from star formation to high energy physics, including the interactions of supernovae shocks with interstellar clouds, the formation of low and high mass stars, accretion onto neutron stars, and Compton-heated winds from accretion disks.
This has prompted theorists ( Soker & Rappaport 2000 ; Frank & Blackmann 2004 ) to investigate whether an accretion disk scenario, similar to the model used to explain jets from active galactic nuclei and young stars, could account for both the point symmetry and the high degree of collimation seen in many PPN jets.

accretion and strong
In some cases the magnetic field of the white dwarf is strong enough to disrupt the inner accretion disk or even prevent disk formation altogether.
Radiatively inefficient accretion has been used to explain the lack of strong AGN-type radiation from massive black holes in the centres of elliptical galaxies in clusters, where otherwise we might expect high accretion rates and corresponding high luminosities.
Microquasars are named after quasars, as they have some common characteristics: strong and variable radio emission, often resolvable as a pair of radio jets, and an accretion disk surrounding a compact object which is either a black hole or a neutron star.
These emission lines exhibit strong Doppler broadening, which implies velocities from 500 to 4000 km / s, and are believed to originate near an accretion disc surrounding the central black hole.
The latter have accretion disks and continue to accrete hot gas, which manifests itself by strong emission lines in their spectrum.
John W. Pettit, while stating, " Mahayana has not got a strong historical claim for representing the explicit teachings of the historical Buddha ", also argues that the basic concepts of Mahāyāna do occur in the Pāli canon and that this suggests that Mahāyāna is " not simply an accretion of fabricated doctrines " but " has a strong connection with the teachings of Buddha himself ".

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