Physics of stars

Copyright © 2010 by Stanislav Kozlov

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The nature of supernova explosion depends on many factors:

    – The mass of the former star,

    – Masses of the «white dwarf» and the «neutron star»,

    – Velocity of dynamic processes in discharged outer space,

    – Speed of chain reaction of the transuranium elements in the «white dwarf» and so on.

Collectively, these and other characteristics determine the type and nature of the supernova star.

Let’s draw the possible scheme of development of a star at the end of its life.

In the case if there would be no gas and dust in outer space or in the case of low content of gas and dust, the scheme would have a view, as shown in Illustration № R-9.12. 

 In planets that are former «white dwarfs» who passed the stage of «neutron star», the level of density is might be higher than the planets that haven’t passed the stage of «neutron star».
It is possible that planets with a high density, but with a smaller sizes, the star was severe, than the planet that had the same density, but larger. That’s because during the explosion of the «white dwarf», the heavier star eject more mass into space, than the «white dwarf» star with smaller mass. 

So we have determined that at the end of stars’ life, the «white dwarf» remains on the spot of a star of medium mass, in which the mass of heavy elements that can participate in the fission chain reaction, is above the «critical». 

In the «white dwarf» a chain reaction of fission is starting. At this time, under the influence of the vacuum formed around the «white dwarf», suction of gas and dust from outer space takes place. That’s often leads to resumption of synthesis of light kernels in the stellar atmosphere.
The combination and interaction of these two processes and nuclear explosions perhaps determine the variety of supernova stars.
«Critical mass» of transuranic elements cannot be regarded as a cluster of total mass of these elements, because the process of fission neutrons is influenced by many factors. For example, the mass of fissionable material can be more critical, but the density of the location of these kernels is low and the chain reaction may increase with a low rate, and may decay.
It’s impossible to speak about a stable, or stationary fission process in the «white dwarf», because the substance in the «white dwarf» is might be in a molten state and continuously mixed, which also affects the rate of fission. Temperature variations in different parts of the «white dwarf» also have influence on the rate of nuclear fission. Thus, in the management of uranium reactor, the method of power change is used in expense of the temperature changes in the «active zone».
Consider the scenario where life of the Sun comes to end.
Since the Sun referred as a star of small mass, the explosion of the «white dwarf» at the expense of the chain reaction cannot occur. But, given that the Sun is in the sleeve of the galaxy «The Milky Way», where space has a lot of gas and dust, it is possible that an outbreak of a supernova of type 2 will occur, and also the recurrence of such outbreaks is possible. Also, the disruption of the atmospheric envelopes of planets and their absorption into the space around the «white dwarf» might take place. Since, the mass of the star decreases, it is possible that some planets in the solar system would lose its orbit and go into space, look for other stars.
And it is possible that the volume and other parameters of the vacuum is not enough for the ignition of a supernova from the Sun.

      End of life of stars of large mass

In stars with large mass, the processes of synthesis are going on high speed.
Along with the increasing mass of the star its radius and volume increases as well. In a linear increase, the radius of the star volume increases in a cubic dependence.
In chapter 2 «Physical basis of analysis astrophysics», in the «Spherical shape of stars» section, we considered the possible change in the parameters of the stars when the size is changing. Let’s recall the conclusions that we reached as a result of this analysis.
Taking as an example a star with radius: 1Rs (one radius of the Sun); 2Rs (two solar radius); 3Rs (three solar radii) and 5Rs (five solar radii). Where Rs – radius of the Sun. We calculated the change in pressure at different levels, in these stars, and the results of calculations were inserted into

graph № G-2.5. This graph shows that the increasing radius of the star increases the dynamic pressure in its bowels in square dependence. Thus, a star with a radius of two solar radii, at the level of the radius of the Sun, the solar pressure is higher by four times. With a radius of three stars of solar radius, the pressure increases up to nine solar. With a radius of five stars in solar radii – the pressure is increased 25 times. At the level 0.2 solar radius, where the pressure in a star with the radius of the Sun increases by 25 times, the pressure in the star with a radius twice as much than the Sun – the pressure is increased by 100 times. In a star with three radii of the Sun – 225 times more, and a star with five radii of the Sun – 625 times more. That means, the increasing radius of the star increases the compression strength of its mineral resources, which increases the rate of nuclear synthesis, and increases the probability of synthesis of heavy kernels. 

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