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Nucleosynthesis: Elements from Stars
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Stellar nucleosynthesis is the collective term for the nuclear reactions taking place in stars to build the nuclei of the elements heavier than hydrogen.
The production of new elements that occurs naturally in stars via nuclear reactions, and in supernova explosions. Nucleosynthesis is also an important part of alchemics.
Big bang nucleosynthesis refers to the process of element production during the early phases of the universe, shortly after the Big Bang. It is believed to be responsible for the formation of hydrogen, its isotope deuterium, helium in its varieties 3He and 4He, and the isotope of lithium 7Li.
Big Bang nucleosynthesis
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Big Bang Nucleosynthesis
Gamow, Alpher and Herman proposed the hot Big Bang as a means to produce all of the elements. However, the lack of stable nuclei with atomic weights of 5 or 8 limited the Big Bang to producing hydrogen and helium.
Nucleosynthesis is the process of creating elements by nuclear reactions (5). The Syllabus requires that you are able to "discuss the synthesis of elements in stars by fusion".
Nucleosynthesis and Fusion Reactions
Nucleosynthesis simply refers to the production of nuclei heavier than hydrogen. This occurs in main sequence stars through two main processes, the proton-proton chain and the CNO cycle (carbon, nitrogen, oxygen).
(a) The transformation of one element or isotope into another. Nucleosynthesis occurred just after the big bang, but today most nucleosynthesis takes place in stars - for example, the Sun presently converts hydrogen into helium.
Nucleosynthesis: Element formation by reactions inside stars.
Nucleus: (see comet) Kilometer-sized "dirty snowball" composed of dust (refractory material) and primarily water-ice which gives rise to all of the features observers associate with comets.
The processes whereby elements heavier than hydrogen are built up from hydrogen.
Nucleosynthesis - The building up of more massive elements from less massive elements through nuclear reactions in stars
Nucleoitide - The class of organic molecules of which nucleic acids are composed ...
Nucleosynthesis Era, time=3 minutes, Temperature = 109 K.
Figure 2. Click to see a larger version. This graph shows how the composition of the Universe changed with time since the Big Bang - not much time, though.
Nucleosynthesis and non-baryonic dark matter
As we've seen, there is strong evidence that galaxies contain a great deal of dark matter: the gravitational mass appears to be larger than the visible mass by factors of a few to perhaps one hundred.
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stellar nucleosynthesis The formation of heavy elements by the fusion of lighter nucleii in the hearts of stars. Except for hydrogen and helium, all other elements in our universe result from stellar nucleosynthesis.
Nucleosynthesis requires a high-speed collision, which can only be achieved with very high temperature. The minimum temperature required for the fusion of hydrogen is 5 million degrees. Elements with more protons in their nuclei require still higher temperatures.
Nucleosynthesis The creation of new elements in stars by combining lighter nuclei to make heavier nuclei.
More about nucleosynthesis...
Nucleosynthesis: The First Atoms
When the universe had been in existence for 1 second, it had cooled to approximately 1010 K (2x1010 °F) (1000 times hotter than the core of the sun). Finally, light atomic nuclei could form.
Nucleosynthesis Spacesuits Rovers Water Life Radiation Seasons Gravitational Waves Wolf-Rayet Stars Rockets Elevation Experiments Singularities Panspermia Homogeneity Aurora Asteroids Nova Sunlight Thermodynamics
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Nucleosynthesis is the production of new elements via nuclear reactions. Nucleosynthesis takes place in stars. It also took place soon after the Big Bang.
Nucleosynthesis: The process by which nuclear reactions produce the various elements of the periodic table.
nucleosynthesis Process whereby helium and the heavy elements are created from hydrogen.
Why is nucleosynthesis in the Big Bang different from nucleosynthesis in stars?
The answer lies in the particles present in the early Universe and the temperatures and densities present when nuclear reactions are occurring: ...
The fusion of light elements during the early hot phase of the big bang, to produce heavier elements. It resulted in nearly a quarter of the mass of the universe being turned from hydrogen into helium.
cosmic rays ...
Big Bang Nucleosynthesis
Big Bang nucleosynthesis refers to the production of nuclei other than those of 1H (i.e. the normal, light isotope of hydrogen, whose nucleus consists of a single proton) during the early phases of the universe.
Element building that occurred in the early universe when the nuclei of primordial matter collided and fused with one another. Most of the helium in the universe was created by this process.
BIG BANG NUCLEOSYNTHESIS - Formation of elements in the Big Bang. Calculated abundances of these isotopes (D (deuterium = 2H), 3H, 3He, 4He, 6Li, 7Li, and 7Be) and of protons (1H) and neutrons (n) vs. time are shown in the diagram.
Primordial nucleosynthesis also depends on the number of flavors of neutrino; the more there are, the more neutrons will be produced in the early universe and the more helium will remain. The value above implies only three kinds of leptons, fortunately allowed by the three known generations.
(a) The creation of elements that occurred just minutes after the Big Bang. According to standard theory, primordial nucleosynthesis gave the Universe only five nuclei, all lightweight: hydrogen-1, hydrogen-2 (or deuterium), helium-3, helium-4, and lithium-7. [C95] ...
This is an important step in the process of nucleosynthesis.
RR LYRAE VARIABLES: A variable star that has a regularly varying luminosity. These stars all have about the same luminosity making them suitable for obtaining distances.
Nuclear Fusion and Nucleosynthesis
Stars are giant nuclear reactors. In the center of stars, atoms are taken apart by tremendous atomic collisions that alter the atomic structure and release an enormous amount of energy. This makes stars hot and bright.
The first three minutes / big bang nucleosynthesis, deuterium
Microwave Background Radiation: recombination, anisotropy, Sunyaev-Zeldovich effect
dark matter: MACHO, WIMP, neutrino
de Sitter space, Friedmann-Robertson-Walker metric(*), Newtonian derivation of the Friedmann equation ...
The term "Primordial Nucleosynthesis" refers to the production of chemical elements with more than one proton a few moments after the Big Bang. This production happened in a very short time, allowing only hydrogen, helium, and lithium to form, but no heavier elements.
Hoyle later helped considerably in the effort to understand stellar nucleosynthesis, the nuclear pathway for building certain heavier elements from lighter ones. After the discovery of the cosmic microwave background radiation in 1964, and especially when its spectrum (i.e.
Sir Fred Hoyle Fellow of the Royal Society was an England astronomer primarily remembered today for his contribution to the theory of stellar nucleosynthesis and his often controversial stance on other Cosmology and scientific matters, in particular his rejection of the Big Bang theory....
This brings us to the important issue of nucleosynthesis, or the creation of the nuclei. The universe is mostly composed of hydrogen and helium. All the rest of the elements of the periodic table are built up in the interior of stars through nuclear reactions.
Hydrogen (deuterium) helium and some lithium were created by nucleosynthesis just after the Big Bang. The next heaviest elements (like carbon, nirogen, and oxygen) are formed inside stars via fusion. Most stars fuse hydrogen, forming helium.
These heavier elements were not present when the universe formed and could only be created through nucleosynthesis within the cores of stars. Although globulars as a group are metal deficient they are divided into metal poor and metal rich groups.
The primordial nucleons (hydrogen and helium) themselves were formed from the quark-gluon plasma in the first few minutes after the Big Bang, as it cooled to below ten million degrees, but nucleosynthesis of the heavier elements (including all carbon, oxygen, etc) occurs primarily in the nuclear ...