Sun

Fortunately 700 000 km (beam of the Sun) of matter, isolate them from the space global inter. Superficial layers appears a powerful wind which propagates in the space.
Subjected to these squalls, comets are decorated with a tail showing the solar direction. The Earth is not totally sheltered by its magnetic folding screen, the wind infiltrates by polar cracks, to show us these magnificent auroras borealis of white, green, red lights.
The Sun got egoistically 99 % of the total mass of the dust and the gas of the original nebula of the system.
Planets being only a residue of this gravitational evolution.

TESIS The observatory was designed by the Laboratory of X-ray astronomy of the Sun of the Lebedev Institute.
It is designed to study solar activity and space weather, the warming of the solar corona, the mechanism of flares and the solar cycle.
TESIS should take a million pictures of the Sun.
The probe-Photon Koronas a weight of 1920 kg (payload of 600 kg) was launched on 30 January from the Russian Plesetsk cosmodrome in the Arkhangelsk region.
This is the third probe type KORONA (initial Russian orbital space circumterrestrial Observations on the activity of the sun).

huge protuberance taken by TESIS, imagine the size of the protrusion compared to the size of the Earth represented in blue, top right of the image.

" The universe needed places denser than the galaxies, to reach the complexity, it invents then stars " Trinh Xuan Thuan. Pushed by the gravity, the small clouds of hydrogen and helium of the young galaxy, collapse and the density increases gradually. The gaseous balls ignite, it is the birth of stars as the Sun. The nuclear energy loosened in its balls, stop the gravitational collapse and a balance settles down between the pressure of the radiation and that of the gravity.

The big stars live some million years, stars average as our Sun, exhaust their reserve of hydrogen only at the end of 9 billion years and the small stars will burn their fuel, 20 billion for years. When the hydrogen is consumed, the gravitational pressure gets over it, the density increases and the temperature reaches 100 million degrees.
The nuclei of helium 4, produced by the combustion of the hydrogen, group together to form nuclei of carbon 12.

The pressure of the radiation resumes vigor, the contraction stops, the star swells excessively, cools and becomes a red giant.

300 million years later, the combustion of the helium is ended, the heart of the red giant contracts again, for lack of a sufficient radiation. The temperature reaches then 500 million degrees, and it is now in the tour of the carbon to waste away for make the other elements always more complex, as the neon, the oxygen, the sodium, the magnesium, the aluminum, the silicon, the phosphor, the sulfur.

In the stars of solar type, a suite of reactions called " chain proton-proton " operates in several stages.
At first 2 protons merge in a nucleus of deuterium (isotope of the hydrogen or the heavy hydrogen, because formed by a proton and by a neutron) with emission of a positron (or antielectron) and of neutrinos which take 2 % of the global energy. The deuterium merges with a proton to give a nucleus of helium 3 (2 protons and 1 only neutron) and a photon; two of these unstable nuclei merge to lead to the very unstable beryllium 6 which splits at once to give finally the stable nucleus of helium 4 with formation of 2 protons.
6 protons are thus necessary so that a stable nucleus of helium can form, with restoration of 2 protons; the balance sheet is many 4 protons for a nucleus He4.
Chains protons-protons require a temperature superior to 10 million degrees. A small quantity of helium 3 forms of the beryllium 7, which, during the other chains of reactions, leads to the lithium 7 or to the boron 8 giving of the beryllium 8 (with intense release of neutrinos): all these nuclei, very unstable, quickly transmute in helium 4. To know more about it, read " Life and death of stars " of Agnès Acker and Ariane Lançon.

An article on the trip of the photon

The death of a star can be sweet or rapes, it depends on its mass.
Below 1,4 times the mass of the Sun, the star goes out in the serenity, it will pass of the size of a red giant (approximately 50 million Km of beam), in that of the Earth (approximately 6000 km of beam). The star becomes a white dwarf.
Between 1,4 and 5 times the mass of the Sun, its agony is much more violent. Its beam narrows until 10 Km. The final density is enormous, nuclei cannot resist and the heart of the star becomes a gigantic nucleus of neutrons. The collapse provokes a terrible explosion which is going to throw the superior layers of the star in the space and we shall see shining in the sky, a supernova.
Above 5 times the mass of the Sun, the collapse is extremely violent. This one cannot be any more arrested. The heart of the star A black hole becomes.
The violence of the collapse produces a gigantic explosion which throws the superior layers of the star in the space.

 As in the previous case a supernova is going to extend, on hundreds of billion Km, sowing the interstellar middle of heavy elements, made during the life of the star and during the explosion.

The violence of the collapse of a star, produces a huge explosion which projects the upper layers of the star into space, playing a key role in the history of life.
During its supernova explosion the star releases the chemical elements that it has synthesized in its existence and in the explosion itself. These chemicals travel in the interstellar medium to spread into space.