Compact Object
A star that has collapsed to form a white dwarf, neutron star or black hole.
Comparative Planetology ...
[edit] Compact object
There is some uncertainty about the mass of the compact object. Stellar evolutionary models suggest a mass of 20 ± 5 solar masses,[7] while other techniques resulted in 10 solar masses.
If the compact object in an X-ray binary is a neutron star with a powerful magnetic field, the gas accreted from the companion star will be channelled to the magnetic poles of the neutron star.
"When two compact objects ("point masses" in phystalk) act on each other, they accelerate in opposite directions, and the ratio of their accelerations is always the same. " ...
Other extremely compact objects such as neutron stars can also have photon spheres.
Neutron stars are compact objects that are created in the cores of massive stars during supernova explosions.
accretion disks (Spacetime Wrinkles Glossary) In a binary system containing a star and a compact object (white dwarf, neutron star, or black hole) gas may flow from the star to the compact object.
* The first light image, of supernova remnant Cassiopeia A, gave astronomers their first glimpse of the compact object at the center of the remnant, probably a neutron star or black hole. (Pavlov, et al, 2000) ...
Now you may have a picture in your mind of a dense, compact object sitting there "sucking" light onto its surface.
Compact objects cannot escape detection in complete spectroscopic studies of faint samples, while low-surface-brightness (LSB) objects require very deep imaging studies.
Jets of this sort are apparently quite common in astronomical systems in which an accretion disk surrounds a compact object (such as a neutron star or a black hole).
The central bulge contains at its core a very massive compact object; under the theory of general relativity, this compact object is a black hole. The mass of the central object is estimated to be 3.6 million times the mass of the Sun.
We've already run across quite a few exotic, compact objects like black holes, neutron stars, and white dwarfs in our discussion of stars. There are also all those really ultra-faint L and T type stars that would be difficult to detect.
The system pairs a hot, massive star with a compact object, thought either to be a neutron star or a black hole, that blasts twin radio-emitting jets of matter into space at more than half the speed of light.
The mass of the compact object probably is considerably higher than >3 Msun. The Cygnus X-1 binary system, discovered in 1965, consists of a O9.7 Iab type supergiant and a compact object orbiting with a period of 5.6 days.
Scorpius X-1 is a low-mass X-ray binary, which means that it consists of a massive, compact object like a neutron star or a black hole, and a low-mass stellar companion.
Densities range from a maximum of only a million atoms and electrons per cubic centimeter for the most compact objects down to under 10 for the huge ones that are dissipating into interstellar space.
Hence, for the most part, observations of accretion disks and orbital motions merely indicate that there is a compact object of a certain mass, and says very little about the nature of that object.
black holes A dense, compact object whose gravitational pull is so strong that - within a certain distance of it - nothing can escape, not even light.
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.
A rotating disk of gas surrounding a compact object (such as a neutron star or black hole), formed by material falling inward.
albedo - (n.)
Fraction of incident electromagnetic radiation reflected by a body such as a planet, star, or cloud.
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)
The centers of active galaxies that are emitting large amounts of excess energy.
When a massive star explodes, it leaves behind some sort of compact object, either a city-sized ball of subatomic particles called a neutron star, or a black hole. The outcome depends on the mass of the progenitor star.
One possibility for dark matter is massive compact objects (MACHOs) such as cool dwarf stars, dead stellar remnants - neutron stars or black holes - and planet-sized collections of rock and ice.
A binary pulsar discovered in 1974, probably consisting of a neutron star and an even more compact object in an eccentric orbit, with an orbital period of 0.3230 days and a pulsation period of 59 milliseconds. (PSR 1913+16) [H76]
Hund's Rule ...
It is a binary star system that includes a blue supergiant variable and a compact object, one that cannot be classified with certainty but is small for its mass, e.g. a white dwarf, a neutron star or a black hole.
The Eddington limit, the natural limit to the luminosity of stars, or the radiation generated by accretion onto a compact object, is named in his honour....
Comparing the brightness of compact objects heavier than 3 solar masses with those lighter than 3 solar masses, shows that the heavier masses are dimmer than the lighter masses even if they have the same orbital periods.
Stanley Eddington (December 28, 1882 - November 22, 1944) was arguably the most important astrophysicist from the early 20th century. The Eddington limit, the natural limit to the luminosity that can be radiated by accretion onto a compact object, ...
(1910 - 1995): Indian astrophysicist reknowned for creating theoretical models of white dwarf stars, among other achievements. His equations explained the underlying physics behind the creation of white dwarfs, neutron stars and other compact objects.
are strong indications from the rotation of galaxies about their centres that there is also some form of dark matter accounting for a substantial fraction of the mass in the outer regions. This material might consist of dim stars or compact objects ...
This indicates a very compact object. This and the fact that there was no hint of eclipsing in the spectrum, made it difficult to see whether or not this is a binary system.
 See also: Black Hole, Energy, X-ray, Light, Universe
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