Primordial nucleosynthesis and stars - alchemical cauldrons of the universe

AstroNuclPhysics ® Nuclear Physics - Astrophysics - Cosmology

COSMIC NUCLEAR ALCHEMY and/or ON THE ORIGIN OF ELEMENTS        Structure of matter and nuclear physics Primordial nucleosynthesis at the beginning of the world Stars - alchemical cauldrons of universe We are all descendants of the stars ! Vojtech Ullmann p h y s i c i s t In the lecture on the relationship between nuclear physics and astrophysics and cosmology, we will approach a fascinating scenario of the formation of elements in space and the chemical evolution of the universe at various stages of its evolution.

S y l a b u s

NATURE - NATURAL SCIENCE

MACROWORLD 10 ^-8 cm <d <10 ³ light years
Classical physics (Newtonian mechanics, thermodynamics, electrodynamics ...)

MICROWORLD - inside the matter d <10 ^-8 cm
Quantum physics, atomistics, nuclear physics , elementary particles

MEGA-WORLD - distant universe d > 10 ³ light years
Special theory of relativity - high velocities ® time dilation, length contraction
General theory of relativity - gravity ® curved spacetime
Astrophysics + Cosmology

Matter - substance
Basic question :
What is the essence and internal composition of matter ?

What is the carrier of the properties of substances?
Substance properties: alchemy ® chemistry ® physics ; Chemical properties Þ e l e m e n t s

CONTRIBUTION OF ATOMIC AND NUCLEAR PHYSICS
- deep penetration into the interior of matter -

Understanding the structure of matter - What is the carrier of the properties of substances? - Atoms!
Atomic Physics: structure of atoms Þ substance chemistry

Thomson "pudding" model     ;    Rutherford scattering experiments Þ planetary model  
ÞBohr model 

The "boss" of an atom is the atomic nucleus :
The structure and properties of the atom are given by the structure of its nucleus
- the number of Z protons in the nucleus determines the electronic configuration of the shell and the occupation of the valence shell -

Core dimensions: » 10 ^-13 cm (100,000 times smaller than an atom!), Density r» 10 ¹⁴ g / cm ³
ß
Hopelessness of medieval alchemy's efforts to transmutate elements !
(they had no idea about the nucleus, they "scraped" atoms only on the valence shell)
Paradox: alchemists were often also astronomers - they had no idea, that stars that observe at night, can do
what they try in vain on a large scale for billions of years!

Nuclear physics: structure of atomic nuclei, strong and weak (nuclear) interactions

Understanding the properties of elementary particles
- leptons, baryons, hadrons
- quarks, gluons ...
- particles - antiparticles

Unitary field theory
electroweak interaction - GUT (grandunified theory) - Supergravity - Superstrings

Scheme various stages and processes unification of four fundamental interactions in nature (see more datail §B.6 "Unification of fundamental interactions. Supergravity. Superstrings." in book "Gravity, black holes, and space - time physics").

Radioactivity and nuclear reactions

• spontaneous nuclear transformation - radioactivity
  

• properties of ionizing radiation a , b , g
• radiation detection and spectrometry
• production of radionuclides by nuclear reactions
  

Reaction (n, g) - slow neutron radiation capture - production of b^- emitters in the reactor
⁹⁹Mo(® ^99mTc), ¹³¹J, ⁵⁹Fe, ⁶⁰Co, ¹³⁷Cs, ¹³³Xe, ......
Reaction (p, g) - production of b⁺-radiators in accelerator (cyclotron)
²⁰¹Tl, ⁶⁷Ga, ¹¹¹In, ⁸¹Rb(® ^81mKr), ¹⁸F, ¹⁵O, ¹¹C ........

Industrial use of radiation
Defectoscopy, X-ray fluorescence analysis, neutron activation analysis ...

Biological use of radiation

• X-ray radiodiagnostics
• radiotherapy
• nuclear medicine
  radionuclide diagnostics (especially scintigraphy)
  therapeutic applications of radionuclides (eg thyroid ¹³¹J)
• nuclear magnetic resonance

Binding energy of nucleons in nuclei ® nuclear energy

Energy recovery from atomic nuclei - Nuclear energetics

• fission of uranium in reactors
  

²³⁵ U + n ® ^{» 140} X + ^{» 90} Y + (2-3) n (+ 200 MeV); ²³⁸ U + n ® ²³⁹ U ® ( b ^- ) ²³⁹ Pu ® fission .....

- about 0.9 MeV / nucleon is released Þ efficiency: < 0.1% from E = mc ²

• nuclear fusion - thermonuclear reaction H ® He (+ 25 MeV)
  
            Inertial (laser) fusion                             Fusion in magnetically held plasma - tokamak
               - about 7 MeV / nucleon is released Þ efficiency: » 0.7% E = mc ²

Our terrestrial efforts to use nuclear energy are just clumsy attempts
to emulate what stars have been able to do for billions of years!
What are we missing? - Strong gravity.

Basic question :
Where did the elements come from in nature ?

ASTROPHYSICS - physical phenomena in universe

Nuclear astrophysics
Application of the laws and phenomena of nuclear physics to processes taking place in universe

COSMOLOGY - structure and evolution of the universe as a whole

Origin, development and end of the closed universe :

Early universe - the "big bang" - hadron era ß lepton era - primordial nucleosynthesis ß era radiation ß era substances - formation of clusters of galaxies, galaxies, stars ß Another nucleosynthesis takes place until in the stars The end of the universe: open universe Þ thermal death closed universe Þ big crunch Hidden matter: “Brown dwarfs”? Black holes? Neutrinos (rest mass?) ? Other "exotic" particles?

Pre - big-bang phase + big bang itself: neither nucleons nor nuclei of atoms existed.

1. Hadron era ~ 10 ^-6 s <t ~ 10 ^-4 s, r > 10 ¹⁴ g / cm ³ , T> 10 ¹² °K
The majority of matter in space was formed by a mixture of emerging and annihilating heavy particles and antiparticles with a strong interaction (protons, neutrons, mesons, hyperons - ie hadrons), whose number was about the same as photons and neutrinos; there is a thermodynamic equilibrium between all these particles. The strong interaction between hadrons plays a dominant role here .
Baryon asymmetry : an excess of nucleons, about 1 baryon per 10⁸ particles.
Particle formation

2. Lepton era ~ 10 ^-4 s <t <~ 10 s, ~ 10 ¹⁴ g / cm ³ > r > ~ 10 ⁴ g / cm ³ , ~ 10 ¹² > T> ~ 5.10 ⁹ °K
When the temperature drops so much, that kT ( k is Boltzman's constant) is significantly lower than the resting energy of the proton, nucleons and antinucleons annihilate each other (due to baryon asymmetry except for the small surplus of nucleons, which led to the formation of the substance now in space); the mass of the universe then mainly consisted of an equilibrium mixture of light particles - photons, electrons, positrons, neutrinos and antineutrinos.

The Lepton era free neutrons are unstable - "rescue" of neutrons in helium - ß primary nucleosynthesis

3. Radiation era ~ 10 s <t <~ 10 ¹³ s @ 300,000 years, ~ 10 ⁴ g / cm ³ > r > ~ 10 ^-21 g / cm ³ , ~ 10 ¹⁰ °K> T> 3.10 ¹⁰ °K
At the beginning of this stage (also called the radiation-dominating era of the photon plasma), the synthesis of helium and the annihilation of electrons with positrons are still complete. When the energy of the primary photons dropped below 0.5 MeV, which corresponds to the rest energy of the electron, the radiation ceased to have a significant effect on the further evolution of the elements in universe.
- from the point of view of nucleosynthesis, nothing happens

4. The era of matter (post-recombination period),
which begins with the completion of recombination (approximately 300 00 years after the Big Bang) and continues to this day. The temperature of the substance , which becomes the main carrier of energy-mass, decreases as a^-2 during expansion and should currently reach only about 10 ^-2 °K; the temperature of the separated "relic" radiation, changing as a^-1, dropped from the original 3000 °K to today's about 2.7 °K. The expansion of the universe transformed what was once light into microwaves.

Formation of large-scale structure of the universe ß The formation of galaxies and clusters of galaxies ß Stars formation

The story of cosmic nucleogenesis continues and graduates !
or
Thermonuclear reactions inside stars

Districts can form in a shrinking cloud in which gravitational contractions occur faster than in the surroundings (gravitational instabilities). From these individual districts, protostars are formed and finally stars, which usually form in groups.

Thermonuclear reactions as a source of energy for stars

a) direct proton-proton reaction (p = ¹ H)

1st partial reaction: ¹ H + ¹ H ® ² D + e ⁺ + n (+ 1.44 MeV)
2nd partial reaction: ² D + ¹ H ® ³ He + g (+ 5.49 MeV)
3rd part Reaction: ³ He + ³ He ® ⁴ He + 2 ¹ H (+ 12.85 MeV)

Total energy balance: release 26.2 MeV = 4.2.10 ^-12 J / core He

b) CNO cycle

1st partial reaction: ¹² C + ¹ H ® ¹³ N + g (+ 1.95 MeV)
2nd partial reaction: ¹³ N ® ¹³ C + e ⁺ + n (+ 2.22 MeV)
3rd partial reaction: ¹³ C + ¹ H ® ¹⁴ N + g (+ 7.54 MeV)
4th partial reaction: ¹⁴ N + ¹ H ® ¹⁵ O + g (+ 7.35 MeV)
5th partial reaction: ¹⁵ O ® ¹⁵ N + e ⁺ + n (+ 2.71 MeV)
6th partial reaction: ¹⁵ N + ¹ H ® ¹² C + ⁴ He (+ 4.96 MeV)

Total energy balance: release 25.0 MeV = 4.0.10 ^-12 J /1 core He

General :
The binding energy of each proton in the He nucleus is 0.007 m₀.c ²
Þ Thermonuclear hydrogen combustion efficiency: » 0.007 m₀.c ² ( » 0.7% )

⁴ He + ⁴ He ® ⁸ Be + g
⁸ Be + ⁴ He ® ¹² C + g (+ 7.4 MeV)

May continue at rising temperature: (if there is still enough helium)

¹² C + a ® ¹⁶ O + g (+ 7.15 MeV)
¹⁶ O + a ® ²⁰ Ne + g (+ 4.75 MeV)
²⁰ Ne + a ® ²⁴ Mg + g (+ 9.31 MeV)
etc. ......

• Nucleosynthesis of heavier elements

¨ a - process: the capture of particles a , reacting (a , g) - typically up to ⁴⁰ Ca

¨ neutron capture ; subsequent b^- - decay :
^N A _Z + n ⁰ ® ^{N + 1} B _Z + g ; ^{N + 1} B _Z (b ^- ) ® ^{N + 1} C _{Z + 1} + e ^- + g

Slow capture n⁰ (s-process - proceeds slower than b-decay); - up to N = 210
Rapid capture of neutrons (so-called r -process - repeated capture, faster than b-decay); - mostly in the final stages and during a supernova explosion
(and also in the nucleonization of neutron matter ejected during neutron star collisions) ...

Nucleosynthesis up to Fe - exothermic process
Nucleosynthesis over Fe - endothermic reactions - takes place only in the final stage of stars

How do the heavier elements "cooked" by the star get into the surrounding universe ?
or
The final stages of the life of the stars

White dwarf (if the remaining mass of the star is < 1.5 Sun)

End of a massive star: M Supernova explosion

• 1st consequence: ejection of synthesized elements (up to iron)
  Pushing e^- into nuclei, absorbing them and merging with p⁺ (K-capture analogy)
  e ^- + p ⁺ ® n ⁰ + n (+ g ) Þ neutron star (at M < 2 M_¤)
  explosion Þ ejecting heavier elements from the interior of the star into surrounding space
      
• Consequence 2: synthesis of heavy elements (up to transurans)
  Huge number of neutrons Þ repeated neutron fusion Þ formation of even the most heaviest elements
  neutron capture ; subsequent b^- - decay :
  ^N A _Z + n ⁰ ® ^{N + 1} B _Z + g ; ^{N + 1} B _Z (b ^- ) ® ^{N + 1} C _{Z + 1} + e ^- + g ; etc ... etc ... etc ...

Supernova explosion observed in 1054 in China	Today, a Crab Nebula containing a pulsar inside - a rapidly rotating neutron star - is observed at that place

Fusion of neutronon stars
Another way of creating heavier elements in space occurs with the close orbit of two neutron stars and their merging - fusion, "collision". In this process, a large amount of neutron matter is ejected, which immediately "nucleonizes" to form atomic nuclei (§4.8, passage "Collisions and fusions of neutron stars") :

This creates a large number of cores, with a relatively higher proportion of heavy elements. Due to the huge number of neutrons, the r-process of rapid repeated neutron capture by lighter nuclei takes place intensively, during which very heavy nuclei are also effectively formed - from the area around iridium, platinum, gold, to a group of uranium.

Relative abundance of elements in nature depending on their proton (atomic) number Z, related to hydrogen Z = 1. Above: The current average representation of elements in universe. Bottom: Occurrence of elements on Earth (in the Earth's crust) and terrestrial planets. Due to the large range of values, the relative representation of the elements (relative to hydrogen Z = 1) on the vertical axis is plotted on a logarithmic scale; however, this can optically distort a large difference in the representation of hydrogen and helium compared to heavier elements, especially in the upper graph.

In terms of origin, all elements can be divided into 3 groups :

• I. Primary (primordial)
  Hydrogen + Helium - "children" of the big bang (hydrogen "firstborn", helium about 3 min younger)
• II. Secondary (stellar)
  Carbon, nitrogen, oxygen, ..., iron, ..., uranium - the "grandchildren" of the Big Bang , the children of the stars ;
  began to form after about 200 million years after the Big Bang - the heavier, the younger -
• III. Tertiary (cosmogenic)
  Lithium, beryllium, boron - distant descendants of the Big Bang: they are formed until later, only by the interaction of cosmic radiation with the already formed heavier elements scattered in space .

Mass: e material - particle, atomic structure î field - distributed form of matter (quantized) Matter in space: e the observed luminous + lightless - baryonic î non-radiant - dark (hidden) matter                     â                     c                                      í dark matter î  dark energy ?   baryonic    ?     nonbaryonic ( nonbaryonic ) According to current estimates, it is in universe : about 73% dark energy ; about 23% dark matter (hidden, non-radiant); only » 4% of ordinary matter " luminous"or absorbing, accessible to observation .

We are dealing here with the evolution of baryon matter composed of protons, neutrons and electrons

Earthly destinies of elements :

Formation of the solar system and planet Earth
ß
selection mechanisms Þ other relative representation of elements in our nature

Gravitational selection factor: higher proportion of heavier elements on planets

| Helium - element of the Sun God |
He - the second most abundant element in the universe (25%)
Inert light gas, the gravity of the Earth will not keep it Þ rare on Earth.
First discovered not on Earth but on the Sun! - ( Helios = ancient Greek sun god ).
(P.Janssen 1868 - the spectral lines of sunlight - unknown "solar" element)
All helium on earth has secondary origin: originated by the a-radioactivity of uranium and thorium
(accumulates in underground premises, along with natural gas)

Time selection factor: all radioactive nuclei with T_1/2 < 10⁸ years have already decayed
(long-term primary radionuclides - potassium ⁴⁰K, thorium ²³²Th, uranium ^235,238U - have been preserved )

> Rare and artificial elements >
Actinides (except thorium and uranium), especially transurans ® radioactive Þ have not been preserved ;
they are produced artificially by nuclear reactions .
Discoveries of new transurans - up to Z = 118 (ununoctium).
Exception from the middle of Medeleev's table: technetium Tc₄₃ - does not have a stable isotope.
All these elements are now created artificially - in nuclear reactors or accelerators.

Cosmogenic elements
The interactions of cosmic radiation with interstellar matter and the Earth's atmosphere cause a number of of nuclear reactions Þ produced cosmogenic elements .

Cosmogenic elements: deuterium , lithium , beryllium , boron - formed by fission of heavier nuclei by hard cosmic radiation
Cosmogenic radionuclides: carbon ¹⁴C , tritium ³H (+ trace amount ^7,10Be, ³²P, ³⁵S, ³⁶Cl )

Appendix 1: Black holes
At M > 2 M _¤ : Complete relativistic gravitational collapse of star Þ black hole

The theorem " black hole has no hair "

Quantum evaporation of a black hole (Hawkin's process)

The Black Hole ® is the place where nuclear physics ends !
The physics of black holes is discussed in detail in Chapter 4 "Black Holes" of the book "Gravity, Black Holes and the Physics of Spacetime".

Appendix 2: Microphysics and cosmology
4 types of interactions in nature :

• Gravitational
• Electromagnetic
• Strong (nuclear) interaction
• Weak (nuclear) interaction

The speculative question :
“ What would happen if God canceled ("turned off") different types of interactions? ”
For a more detailed discussion, see the passage "4 types of interactions in nature", chapter 5 "Elementary particles", in the monograph "Nuclear physics and physics of ionizing radiation" .

Relationship between microphysics and cosmology :
Relativistic cosmology is discussed in detail in Chapter 4 "Cosmology" of the book "Gravity, Black Holes and the Physics of Spacetime".
Unitary theory of fields and particles is discussed in Chapter B "Unitary theory of fields" of the same monograph .

Vojtech Ullmann