Search results
Results from the WOW.Com Content Network
In astrophysics, accretion is the accumulation of particles into a massive object by gravitationally attracting more matter, typically gaseous matter, into an accretion disk. [ 1 ] [ 2 ] Most astronomical objects , such as galaxies , stars , and planets , are formed by accretion processes.
Accretion disk jets: Why do the disks surrounding certain objects, such as the nuclei of active galaxies, emit jets along their polar axes? These jets are invoked by astronomers to do everything from getting rid of angular momentum in a forming star to reionizing the universe (in active galactic nuclei), but their origin is still not well understood.
Pebble accretion is the accumulation of particles, ranging from centimeters up to meters in diameter, into planetesimals in a protoplanetary disk that is enhanced by aerodynamic drag from the gas present in the disk. This drag reduces the relative velocity of pebbles as they pass by larger bodies, preventing some from escaping the body's gravity.
In astrophysics, the Bondi accretion (also called Bondi–Hoyle–Lyttleton accretion), named after Hermann Bondi, is spherical accretion onto a compact object traveling through the interstellar medium. It is generally used in the context of neutron star and black hole accretion. To achieve an approximate form of the Bondi accretion rate ...
The Blandford–Znajek process is a mechanism for the extraction of energy from a rotating black hole, [1] [2] introduced by Roger Blandford and Roman Znajek in 1977. [3] This mechanism is the most preferred description of how astrophysical jets are formed around spinning supermassive black holes.
An X-ray pulsar is a type of binary star system consisting of a typical star (stellar companion) in orbit around a magnetized neutron star.The magnetic field strength at the surface of the neutron star is typically about 10 8 Tesla, over a trillion times stronger than the strength of the magnetic field measured at the surface of the Earth (60 μT).
Accretion (coastal management), the process where coastal sediments return to the visible portion of the beach following storm erosion; Accretion (geology), the increase in size of a tectonic plate by addition of material along a convergent boundary; Accretionary wedge
In planetary science a streaming instability is a hypothetical mechanism for the formation of planetesimals in which the drag felt by solid particles orbiting in a gas disk leads to their spontaneous concentration into clumps which can gravitationally collapse. [1]