Quasistar
Encyclopedia
A quasi-star is a hypothetical type of extremely massive star
that may have existed very early in the history of the Universe. Unlike modern stars, which are powered by nuclear fusion in their cores, a quasistar's energy would come from material falling into a central black hole.
A quasi-star is predicted to form when the core of a large protostar
collapses into a black hole during its formation and the outer layers of the star are massive enough to absorb the resulting burst of energy without being blown away (as they are with modern supernova
e). Such a star would have to be at least one thousand times the mass of the Sun. Stars this large could only form early in the history of the Universe before the hydrogen and helium were contaminated by heavier elements; see Population III stars.
Once the black hole had formed at the core of the protostar, it would continue generating a large amount of radiant energy from the infall of additional stellar material. This energy would counteract the force of the black hole's gravity, creating an equilibrium similar to the one that supports modern fusion-based stars. A quasi-star is predicted to have had a maximum lifespan of about one million years, after which the core black hole would have grown to about ten thousand solar masses. These intermediate mass black holes have been suggested as the origin of the modern era's supermassive black hole
s. Quasi-stars are predicted to have surface temperatures comparable to that of the Sun, but, with diameters of approximately ten billion kilometers or over seven thousand times the diameter of the sun, each one would produce as much light as a small galaxy.
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
that may have existed very early in the history of the Universe. Unlike modern stars, which are powered by nuclear fusion in their cores, a quasistar's energy would come from material falling into a central black hole.
A quasi-star is predicted to form when the core of a large protostar
Protostar
A protostar is a large mass that forms by contraction out of the gas of a giant molecular cloud in the interstellar medium. The protostellar phase is an early stage in the process of star formation. For a one solar-mass star it lasts about 100,000 years...
collapses into a black hole during its formation and the outer layers of the star are massive enough to absorb the resulting burst of energy without being blown away (as they are with modern supernova
Supernova
A supernova is a stellar explosion that is more energetic than a nova. It is pronounced with the plural supernovae or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months...
e). Such a star would have to be at least one thousand times the mass of the Sun. Stars this large could only form early in the history of the Universe before the hydrogen and helium were contaminated by heavier elements; see Population III stars.
Once the black hole had formed at the core of the protostar, it would continue generating a large amount of radiant energy from the infall of additional stellar material. This energy would counteract the force of the black hole's gravity, creating an equilibrium similar to the one that supports modern fusion-based stars. A quasi-star is predicted to have had a maximum lifespan of about one million years, after which the core black hole would have grown to about ten thousand solar masses. These intermediate mass black holes have been suggested as the origin of the modern era's supermassive black hole
Supermassive black hole
A supermassive black hole is the largest type of black hole in a galaxy, in the order of hundreds of thousands to billions of solar masses. Most, and possibly all galaxies, including the Milky Way, are believed to contain supermassive black holes at their centers.Supermassive black holes have...
s. Quasi-stars are predicted to have surface temperatures comparable to that of the Sun, but, with diameters of approximately ten billion kilometers or over seven thousand times the diameter of the sun, each one would produce as much light as a small galaxy.