What is Nucleosynthesis: Definition and 36 Discussions

Nucleosynthesis is the process that creates new atomic nuclei from pre-existing nucleons (protons and neutrons) and nuclei. According to current theories, the first nuclei were formed a few minutes after the Big Bang, through nuclear reactions in a process called Big Bang nucleosynthesis. After about 20 minutes, the universe had expanded and cooled to a point at which these high-energy collisions among nucleons ended, so only the fastest and simplest reactions occurred, leaving our universe containing about 75% hydrogen and 24% helium by mass. The rest is traces of other elements such as lithium and the hydrogen isotope deuterium. Nucleosynthesis in stars and their explosions later produced the variety of elements and isotopes that we have today, in a process called cosmic chemical evolution. The amounts of total mass in elements heavier than hydrogen and helium (called 'metals' by astrophysicists) remains small (few percent), so that the universe still has approximately the same composition.
Stars fuse light elements to heavier ones in their cores, giving off energy in the process known as stellar nucleosynthesis. Nuclear fusion reactions create many of the lighter elements, up to and including iron and nickel in the most massive stars. Products of stellar nucleosynthesis mostly remain trapped in stellar cores and remnants, except if ejected through stellar winds and explosions. The neutron capture reactions of the r-process and s-process create heavier elements, from iron upwards.
Supernova nucleosynthesis within exploding stars is largely responsible for the elements between oxygen and rubidium: from the ejection of elements produced during stellar nucleosynthesis; through explosive nucleosynthesis during the supernova explosion; and from the r-process (absorption of multiple neutrons) during the explosion.
Neutron star mergers are a recently discovered major source of elements produced in the r-process. When two neutron stars collide, a significant amount of neutron-rich matter may be ejected, including newly formed nuclei.
Cosmic ray spallation is a process wherein cosmic rays impact the nuclei of the interstellar medium and fragment larger atomic nuclei. It is a significant source of the lighter nuclei, particularly 3He, 9Be and 10,11B, that are not created by stellar nucleosynthesis.
Cosmic ray bombardment of solar-system material found on Earth (including meteorites) also contribute to the presence on Earth of cosmogenic nuclides. On Earth, no new nuclei are produced, except in nuclear laboratories that reproduce the above nuclear reactions with particle beams. Natural radioactivity radiogenesis (decay) of long-lived, heavy, primordial radionuclides such as uranium and thorium is the only exception, leading to an increase in the daughter nuclei of such natural decays.

View More On Wikipedia.org
  1. gurbir_s

    A Solving this first-order differential equation for neutron abundance

    The time rate of change of neutron abundance ##X_n## is given by $$\frac{dX_n}{dt} = \lambda - (\lambda + \hat\lambda)X_n$$ where ##\lambda## is neutron production rate per proton and ##\hat\lambda## is neutron destruction rate per neutron. Given the values of ##\lambda## and ##\hat\lambda## at...
  2. B

    I Some questions about baryogenesis

    I'm trying to follow Scott Dodelson's Modern Cosmology. Specifically Chapter 3. Coverage of the subject of baryogenesis appears to be missing from Dodleson's book, so I'm trying to reconstruct things on my own. This represents the formula:$$n_p[T]=g_p\space (\frac{k_b\space m_p\space...
  3. S

    Explosive Nucleosynthesis Yields - Abundance Calculations

    If we consider for Oxygen: - Using the solar values from Anders and Grevesse, where O_⊙ = 8.51e-04 and Si_⊙ = 3.55e-05 (abundances number relative to H). - Using the explosion model 40A from Maeda+2003 (Table 2), we know the ejecta mass (in solar units) for: oxygen-16 = 5.99 oxygen-17 =...
  4. A

    B Lithium problem in Big Bang nucleosynthesis?

    I frequently read of the problem that the measured primordial abundance of lithium does not match the amount expected by Big Bang nucleosynthesis theory. However, I see also graphs like these which seem to suggest that everything is as expected. Is this a contradiction or am I misreading the...
  5. CPW

    I Question about stellar nucleosynthesis from a non-expert

    Given that the universe is 13.8 billion years old and our solar system is 4.6 billion years old, less than 10 billion years of star birth, life, and death is necessary to produce the heaviest occurring natural elements. Given what we know about supernova, what is the minimum number of supernova...
  6. bbbl67

    I Nitrogen production in stellar nucleosynthesis?

    So once a star enters the helium fusion stage, it uses the Triple-alpha process to create Carbon from Helium. It then uses the Alpha Ladder process to create Oxygen from Carbon. So my question is, how is Nitrogen, in between Carbon and Oxygen, produced? All I can think of is that either Oxygen...
  7. T

    B Neutron Star Collisions: Creation of Heavy Elements and Their Fate

    When neutron stars collide, heavy elements, such as gold, are created. Are these elements ejected from the system to be found, say, here on earth? Or do they fall back into the newly created black hole?
  8. BadgerBadger92

    How does temperature play a role in nucleosynthesis?

    How does temperature play a role in nucleosynthesis? I am studying the Big Bang, and am wondering how the first hydrogen atoms were made. This is a basic question, and am wondering how they were made.
  9. S

    I Source of Heavier than Iron Nucleosynthesis

    About 10 days ago, I read this in the Nature journal: http://www.nature.com/news/colliding-stars-spark-rush-to-solve-cosmic-mysteries-1.22829?WT.ec_id=NEWSDAILY-20171016 I quote: "Over the past decade or so, astrophysicists had come to believe that this was the most plausible mechanism to...
  10. Buzz Bloom

    I Big Bang nucleosynthesis Wiki Equation for t x T^2

    The following is from https://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis The era began at temperatures of around 10 MeV (116 gigakelvin) and ended at temperatures below 100 keV (1.16 gigakelvin). The corresponding time interval was from a few tenths of a second to up to 103 seconds. The...
  11. S

    Stellar Nucleosynthesis - From Inanimate to Alive

    If the suggestion that all matter, or the vast majority of matter, that makes up the Earth and everything on it, including humans, was originally forged within dying stars and their resulting supernovae, meaning that we are literally constructed from stardust, would the following statement be...
  12. Amrator

    I Energy Released in Stellar Nucleosynthesis

    This is taken from page 226 in Essential Astrophysics by Lang: "The mass defect, ##ΔM##, for a nucleus containing ##A## nucleons, ##Z## protons, and ##A-Z## neutrons is $$ΔM = Z m_p + (A - Z) m_n - m_{nuc}$$ where ##A## is the mass number of the nucleus, ##Z## is the atomic number, ##m_p## is...
  13. H

    I Evidence to support the theory of stellar nucleosynthesis?

    I am aware of the theory of stellar nucleosynthesis, but what evidence do we have to support this theory? Sources are very much appreciated. Thanks!
  14. C

    How Neutrinos Prevent Cavities

    They make fluorine, according to a large new study. Link: ScienceNOW
  15. Y

    Helium formation during nucleosynthesis

    If Helium is a more stable element than Hydrogen, then why wasn't just Helium formed during the process of nucleosynthesis? The matter could just have formed Helium. What was the thing that prevented it?
  16. L

    Plasmatic Ionization in Stellar Nucleosynthesis

    So, I'm not a student in physics. Or astronomy. I'm actually a med student, just fairly curious. In stellar nucleosynthesis, plasma is required to fuse the particles from my understanding. In trying to record all the various reactions (PP Chain, Triple α Process, CNO Cycle), but I can't find...
  17. T

    Confused - nucleosynthesis of carbon

    Confused -- nucleosynthesis of carbon May I ask a question please! I read that nucleosynthesis of carbon was rapid because its one of the excited state energies was only a little higher than the total energy of Be and He. So, the required energy could be obtained through the kinetic energy of...
  18. Q

    Nucleosynthesis of gold in the lab

    Can we make gold from nuclear reaction in the lab? If yes, what are the nuclear equations?
  19. A

    Stellar Nucleosynthesis - What makes it fascinating?

    I've just completed a research assignment on Stellar Nucleosynthesis, and I feel it needs something that will make it stand out. Our class were given the job of researching and investigating a topic that is related to Nuclear Power/Energy/Physics. To obtain top marks, it's essential that...
  20. M

    Question about nucleosynthesis

    I've been reading lately about the origin of the elements and their production in stars and I have a few questions. Let's start by the simple stuff, and correct me if I'm wrong. When stars form and join the main-sequence they burn hydrogen to make helium. At a certain stage when the hydrogen...
  21. P

    Stellar Energy Generation and Nucleosynthesis

    Introduction: The evolution of stellar objects is inherently caused by the chemical composition of the star. Internally, thermonuclear reactions leading to the formation of complex atoms lead to a change in chemical composition which in turn will affect the evolutionary position of a star...
  22. P

    Questions regarding nucleosynthesis

    I'm working on a project for a space habitat, and I want to have the math to back it up. By the way this is not homework, it's just something I do in my spare time. And if you have the links where I can learn more about these things, just provide those and I'll learn on my own. Is there any...
  23. D

    Early universe: equilibrium before nucleosynthesis

    Hi. First of all I apologize because I already posted this topic in the "Homework & Coursework Questions > Advanced Physics" but since it exquisitely concerns astrophysics and it is not getting many answers, I believe it's better to post it here. If a moderator wants to merge the two...
  24. D

    Early universe: equilibrium before nucleosynthesis

    Hi. I am studying the evolution of the universe. In particular, I am reading the history of the universe happening just under a temperature of 100 MeV. At this time, it is said that neutrons and protons are present along with some other particles: electrons, positrons, photons, neutrinos...
  25. TrickyDicky

    Carbon Nucleosynthesis: Exploring Its Role in the Universe's Evolution

    There's this kid mentioned in another thread that seems to raise doubts about carbon nucleosynthesis but the thread was locked, so I thought I'd ask the experts :If all the carbon of the universe is produced in masive stellar fusion nucleosynthesis, is 13 billion years time enough to reach the...
  26. bcrowell

    CMB or nucleosynthesis as empirical tests of gravitation by radiation?

    General relativity predicts that electromagnetic fields contribute to the stress-energy tensor, and that they therefore have gravitational fields. Kreuzer (1968) did laboratory experiments that were interpreted by Will (1976) as confirmation of this prediction in the case of the static electric...
  27. E

    Nucleosynthesis and light curve of Supernovae Ia

    Hi all, I am trying to understand the connection between the specific nucleosynthesis that occurs in each step of the explosion mechanism of type Ia supernova (SN Ia). Let´s see if I got it right, type Ia SN is the complete disruption of a white dwarf(WD) once it passes through the...
  28. jal

    Big-Bang nucleosynthesis (BBN)

    The present big bang theory is available at http://pdg.lbl.gov/2007/reviews/contents_sports.html Big-Bang nucleosynthesis (BBN) marks the boundary between the established and the speculative in big bang cosmology. It does not include the NEW experimental evidence that has been obtained from...
  29. marcus

    LQG corrections to big bang nucleosynthesis

    Three related papers came out today. One posted in astro-ph, and the other two in gr-qc. http://arxiv.org/abs/0710.5734 Dirac Fields in Loop Quantum Gravity and Big Bang Nucleosynthesis Martin Bojowald, Rupam Das, Robert J. Scherrer 15 pages, 2 figures (Submitted on 30 Oct 2007) "Big Bang...
  30. S

    Explain p-process in nucleosynthesis

    could anyone explain p-process in nucleosynthesis for me? i didnt find any suitable site.
  31. M

    Nucleosynthesis with the Big Bang and the Supernovas?

    Why can we only explain the nucleosynthesis with the Big Bang and the Supernovas? Where can I learn more about this subject?
  32. S

    Mathematics in nucleosynthesis

    hey, i don't know if this is the right place for this thread, but i would really be glad if somebody could pls help me out with this! i need a site which would give the mathematics involved in nucleosynthesis. searched the net and the library as best as i could, but i couldn't get any info on...
  33. E

    Nucleosynthesis and Hubble expansion

    How are Nucleosynthesis and Hubble expansion are considered as an evidence for the Big Bang Theory?
  34. B

    S-process model (nucleosynthesis)

    Sorry for all these questions...I just want to be really prepared for the exam I have in a couple of weeks. In the exam we will most likely have to look at the s-process model (it's an exam on the computer) that he showed us in class. He said that we should look at it now to make sure that...
  35. wolram

    Nucleosynthesis of PopIII Core Collapse Supernovae

    http://arxiv.org/abs/astro-ph/0507340 Nucleosynthesis of PopIII Core Collapse Supernovae and the Abundances of Extremely Metal Poor Stars Authors: Marco Limongi (INAF-OAR), Alessandro Chieffi (INAF-IAS) Comments: 6 pages, 4 figure, Proceedings of the IAU Symp. No. 228 "From Lithium to...
  36. wolram

    Neutron diffusion and nucleosynthesis

    http://arxiv.org/abs/astro-ph/0506364 Title: Neutron Diffusion and Nucleosynthesis in an Inhomogeneous Big Bang Model Authors: Juan F. Lara Comments: accepted for publication in Physical Review D This article presents an original code for Big Bang Nucleosynthesis in a baryon...