Nucleosynthesis Definition and 37 Threads

I'm trying to understand why the CNO cycle is considered catalytic in stellar nucleosynthesis. I know that carbon is regenerated in the process, but how does this make the reactions faster than the proton-proton chain? Thanks in advance for your insights!

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...

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...

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 =...

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...

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...

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...

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?

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.

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...

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...

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...

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...

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!

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

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?

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...

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...

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

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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

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

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...

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

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...

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...

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...