Question: Where to free protons originate?
About the article "Proton", section "Abstract".

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 "Between 3 minutes and 20 minutes after the Big Bang" Nucleosynthesis.
During the photon epoch the temperature of the universe falls to the point where atomic nuclei can begin to form.
Protons (hydrogen ions) and neutrons begin to combine into atomic nuclei in the process of nuclear fusion.
Free neutrons combine with protons to form deuterium.
Deuterium rapidly fuses into helium-4.
Nucleosynthesis only lasts for about seventeen minutes, since the temperature and density of the universe has fallen to the point where nuclear fusion cannot continue.
By this time, all neutrons have been incorporated into helium nuclei.
This leaves about three times more hydrogen than helium-4 (by mass) and only trace quantities of other nuclei. 
Although protons have affinity for oppositely-charged electrons, free protons must lose sufficient velocity (and kinetic energy) in order to become closely associated and bound to electrons, since this is a relatively low-energy interaction.
High energy protons, in traversing ordinary matter, lose energy by collisions with atomic nuclei, and by ionization of atoms (removing electrons) until they are slowed sufficiently to be captured by the electron cloud in a normal atom.
However, in such an association with an electron, the character of the bound proton is not changed, and it remains a proton.
The attraction of low-energy free protons to any electrons present in normal matter (such as the electrons in normal atoms) causes free protons to stop and to form a new chemical bond with an atom.
Such a bond happens at any sufficiently "cold" temperature (i.e., comparable to temperatures at the surface of the Sun) and with any type of atom.
Thus, in interaction with any type of normal (non-plasma) matter, low-velocity free protons are attracted to electrons in any atom or molecule with which they come in contact, causing the proton and molecule to combine.
Such molecules are then said to be "protonated", and chemically they often, as a result, become so-called Bronsted acids. 
Physical properties.
Pyridine is a colorless liquid that boils at 115.2°C and freezes at −41.6°C.
Its density, 0.9819 g/cm3, is close to that of water, and its refractive index is 1.5093 at a wavelength of 589 nm and a temperature of 20°C.
Addition of up to 40 mol% of water to pyridine gradually lowers its melting point from −41.6°C to −65.0°C.
The molecular electric dipole moment is 2.2 debye.
Pyridine is diamagnetic and has a diamagnetic susceptibility of −48.7 × 10−6 cm3·mol−1.
The standard enthalpy of formation is 100.2 kJ·mol−1 in the liquid phase and 140.4 kJ·mol−1 in the gas phase.
At 25 °C pyridine has a viscosity of 0.88 mPa/s and thermal conductivity of 0.166 W·m−1·K−1.
The enthalpy of vaporization is 35.09 kJ·mol−1 at the boiling point and normal pressure.
The enthalpy of fusion is 8.28 kJ·mol−1 at the melting point.
Pyridine crystallizes in an orthorhombic crystal system with space group "Pna21" and lattice parameters "a" = 1752, "b" = 897, "c" = 1135 pm, and 16 formula units per unit cell (measured at 153 K).
For comparison, benzene crystal is also orthorhombic, with space group "Pbca", "a" = 729.2 pm, "b" = 947.1 pm, "c" = 674.2 pm (at 78 K), but the number of molecules per cell is only 4.
This difference is partly related to the lower symmetry of the individual pyridine molecule (C2v vs. D6h for benzene).
A trihydrate (pyridine·3H2O) is known; it also crystallizes in an orthorhombic system in the space group "Pbca", lattice parameters "a" = 1244, "b" = 1783, "c" = 679 pm and eight formula units per unit cell (measured at 223 K).
The critical parameters of pyridine are pressure 6.70 MPa, temperature 620 K and volume 229 cm3·mol−1.
In the temperature range 340–426°C its vapor pressure "p" can be described with the Antoine equation formula_1 where "T" is temperature, "A" = 4.16272, "B" = 1371.358 K and "C" = -58.496 K. The optical absorption spectrum of pyridine in hexane contains three bands at the wavelengths of 195 nm (π → π*transition, molar absorptivity ε = 7500 L·(mol·cm)−1), 251 nm (π → π*transition, ε = 2000 L·(mol·cm)−1) and 270 nm (n → π*transition, ε = 450 L·(mol·cm)−1).
The 1H nuclear magnetic resonance (NMR) spectrum of pyridine contains three signals with the integral intensity ratio of 2:1:2 that correspond to the three chemically different protons in the molecule.
These signals originate from the α-protons (chemical shift 8.5 ppm), γ-proton (7.5 ppm) and β-protons (7.1 ppm).
The carbon analog of pyridine, benzene, has only one proton signal at 7.27 ppm.
The larger chemical shifts of the α- and γ-protons in comparison to benzene result from the lower electron density in the α- and γ-positions, which can be derived from the resonance structures.
The situation is rather similar for the 13C NMR spectra of pyridine and benzene: pyridine shows a triplet at δ (α-C) = 150 ppm, δ (β-C) = 124 ppm and δ (γ-C) = 136 ppm, whereas benzene has a single line at 129 ppm.
All shifts are quoted for the solvent-free substances.
Pyridine is conventionally detected by the gas chromatography and mass spectrometry methods. 
The beam pipe is the innermost layer of CDF.
The beam pipe is where the protons and anti-protons, traveling at approximately .99996c, collide head on.
Each of the protons is moving extremely close to the speed of light with extremely high energies.
Therefore, in a collision, much of the energy is converted into mass.
This allows proton- anti-proton annihilation to produce daughter particles, such as top quarks with a mass of 175 GeV, much heavier than the original protons. 
The limit is obtained by setting the outward radiation pressure equal to the inward gravitational force.
Both forces decrease by inverse square laws, so once equality is reached, the hydrodynamic flow is different throughout the star.
From Euler's equation in hydrostatic equilibrium, the mean acceleration is zero,  formula_1 where formula_2 is the velocity, formula_3 is the pressure, formula_4 is the density, and formula_5 is the gravitational potential.
If the pressure is dominated by radiation pressure associated with a radiation flux formula_6,  formula_7 Here formula_8 is the opacity of the stellar material.
For ionized hydrogen formula_9, where formula_10 is the Thomson scattering cross-section for the electron and formula_11 is the mass of a proton.
The luminosity of a source bounded by a surface formula_12 is  formula_13 Now assuming that the opacity is a constant, it can be brought outside of the integral.
Using Gauss's theorem and Poisson's equation gives  formula_14 where formula_15 is the mass of the central object.
This is called the Eddington Luminosity.
For pure ionized hydrogen formula_16 where formula_15☉ the mass of the Sun and formula_18☉ the luminosity of the Sun.
The maximum luminosity of a source in hydrostatic equilibrium is the Eddington luminosity.
If the luminosity exceeds the Eddington limit, then the radiation pressure drives an outflow.
The mass of the proton appears because, in the typical environment for the outer layers of a star, the radiation pressure acts on electrons, which are driven away from the center.
Because protons are negligibly pressured by the analog of Thomson scattering, due to their larger mass, the result is to create a slight charge separation and therefore a radially directed electric field, acting to lift the positive charges, which are typically free protons under the conditions in stellar atmospheres.
When the outward electric field is sufficient to levitate the protons against gravity, both electrons and protons are expelled together.