Quasars are powered by super massive (multimillion solar mass) black holes, spinning rapidly. The spins create accretion disks of galactic size, collapsing, ripping and shredding material into tightly collimated bipolar jets of matter and radiation, spewing highly energized particles out close to the speed of light hundreds of thousands of light years. Some quasar jets exceed a million light years. That kind of energy simply boggles the mind. Quasars are incredible. I had a beautiful poster of one given to me by an astronomer--I wish I could find it again.
Incredibly hot hydrogen burning under gravitational pressure in a continuous thermonuclear fusion reaction. Whilst the centre of the star is incredibly hot (around 15 million kelvin) the area above - The Radiative Zone - is even hotter around 200 million Kelvin! The very centre of the star would be the point of maximum gravitational pressure.
The interior of a stable star is in a state of hydrostatic equilibrium: the forces on any small volume almost exactly counterbalance each other. The balanced forces are inward gravitational force and an outward force due to the pressure gradient within the star. The pressure gradient is established by the temperature gradient of the plasma; the outer part of the star is cooler than the core. The temperature at the core of a main sequence or giant star is at least on the order of 107 K. The resulting temperature and pressure at the hydrogen-burning core of a main sequence star are sufficient for nuclear fusion to occur and for sufficient energy to be produced to prevent further collapse of the star. As atomic nuclei are fused in the core, they emit energy in the form of gamma rays. These photons interact with the surrounding plasma, adding to the thermal energy at the core. Stars on the main sequence convert hydrogen into helium, creating a slowly but steadily increasing proportion of helium in the core. Eventually the helium content becomes predominant and energy production ceases at the core. Instead, for stars of more than 0.4 solar masses, fusion occurs in a slowly expanding shell around the degenerate helium core. In addition to hydrostatic equilibrium, the interior of a stable star will also maintain an energy balance of thermal equilibrium. There is a radial temperature gradient throughout the interior that results in a flux of energy flowing toward the exterior. The outgoing flux of energy leaving any layer within the star will exactly match the incoming flux from below.
A star is a massive, luminous ball of plasma that is held together by its own gravity. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth. Other stars are visible in the night sky, when they are not outshone by the Sun. For most of its life, a star shines due to thermonuclear fusion in its core releasing energy that traverses the star's interior and then radiates into outer space. Almost all elements heavier than hydrogen and helium were created by fusion processes in stars. Astronomers can determine the mass, age, chemical composition and many other properties of a star by observing its spectrum, luminosity and motion through space. The total mass of a star is the principal determinant in its evolution and eventual fate. Other characteristics of a star are determined by its evolutionary history, including the diameter, rotation, movement and temperature. A plot of the temperature of many stars against their luminosities, known as a Hertzsprung-Russell diagram (H-R diagram), allows the age and evolutionary state of a star to be determined. A star begins as a collapsing cloud of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. Once the stellar core is sufficiently dense, some of the hydrogen is steadily converted into helium through the process of nuclear fusion. The remainder of the star's interior carries energy away from the core through a combination of radiative and convective processes. The star's internal pressure prevents it from collapsing further under its own gravity. Once the hydrogen fuel at the core is exhausted, those stars having at least 0.4 times the mass of the Sun expand to become a red giant, in some cases fusing heavier elements at the core or in shells around the core. The star then evolves into a degenerate form, recycling a portion of the matter into the interstellar environment, where it will form a new generation of stars with a higher proportion of heavy elements. Binary and multi-star systems consist of two or more stars that are gravitationally bound, and generally move around each other in stable orbits. When two such stars have a relatively close orbit, their gravitational interaction can have a significant impact on their evolution. Stars can form part of a much larger gravitationally bound structure, such as a cluster or a galaxy.
Broadly speaking the center of most planetary systems is a star.
However when you consider Kepler's 1st Law of planetary motion which states that a planet orbits in an ellipse with the sun at a focus.
(See Related link)/
The material at the center of a nebula clumps together as material is pulled there. This allows a star to form.
a dense- dead star
known as a neutron star
A neutron star is embedded in the center of a nebula.
It could be nothing - just ordinary interstellar space. Or it could be a black hole.
a neutron star
Jo Mama
Shocks from supernovae are the explosions of massive stars.
It is precisely the supernovae that created those elements and dispersed them into space.It is precisely the supernovae that created those elements and dispersed them into space.It is precisely the supernovae that created those elements and dispersed them into space.It is precisely the supernovae that created those elements and dispersed them into space.
It is precisely the supernovae that created those elements and dispersed them into space.It is precisely the supernovae that created those elements and dispersed them into space.It is precisely the supernovae that created those elements and dispersed them into space.It is precisely the supernovae that created those elements and dispersed them into space.
no
supernovae are classified by the lines in their spectra (which indicate which elements are present). type I supernovae have no hydrogen lines, having been caused by the explosion of a star with no hydrogen envelope. type II supernovae have hydrogen lines, indicating that the exploding progenitor star had retained a significant amount of its hydrogen before its supernova. type I supernovae are further classified based on the presence of silicon lines, which are present in type Ia supernovae but not types Ib and Ic.
Black holes do not create supernovae. Black holes are created from a supernovae.
"explode as supernovae". These are called Type II supernovae and sometimes a neutron star is formed, not a black hole.
Shocks from supernovae are the explosions of massive stars.
"Supernovae" is a plural form of "supernova"
It is precisely the supernovae that created those elements and dispersed them into space.It is precisely the supernovae that created those elements and dispersed them into space.It is precisely the supernovae that created those elements and dispersed them into space.It is precisely the supernovae that created those elements and dispersed them into space.
It is precisely the supernovae that created those elements and dispersed them into space.It is precisely the supernovae that created those elements and dispersed them into space.It is precisely the supernovae that created those elements and dispersed them into space.It is precisely the supernovae that created those elements and dispersed them into space.
no
supernovae are classified by the lines in their spectra (which indicate which elements are present). type I supernovae have no hydrogen lines, having been caused by the explosion of a star with no hydrogen envelope. type II supernovae have hydrogen lines, indicating that the exploding progenitor star had retained a significant amount of its hydrogen before its supernova. type I supernovae are further classified based on the presence of silicon lines, which are present in type Ia supernovae but not types Ib and Ic.
Supernovae are massive explosions that occur when a star uses up its gas and explodes so they will only occur once a star has died.
supernovae
See related questions
Nucleosynthesis in supernovae.