WHERE DO ELEMENTS COME FROM?
... 1978 for detection of the Cosmic Microwave Background radiation! • The universe is glowing at 2.73K • This was the Third Great Observation to nail down the Big Bang as real! ...
... 1978 for detection of the Cosmic Microwave Background radiation! • The universe is glowing at 2.73K • This was the Third Great Observation to nail down the Big Bang as real! ...
The Nuclear Fusion Reaction Inside Stars
... 2. What would you expect to happen to elements in a nebula over time? 3. Write a summary of The Fact of the Matter and Nuclear Fusion reactions. 4. How are these two activities related to elements and astronomy? ...
... 2. What would you expect to happen to elements in a nebula over time? 3. Write a summary of The Fact of the Matter and Nuclear Fusion reactions. 4. How are these two activities related to elements and astronomy? ...
Cosmology and Astrophysics II
... neither decays nor combines easily to form heavier nuclei. So out of every 16 nucleons (2 neutrons and 14 protons), 4 of these (25%) combined into one helium-4 nucleus. One analogy is to think of helium-4 as ash, and the amount of ash that one forms when one completely burns a piece of wood is insen ...
... neither decays nor combines easily to form heavier nuclei. So out of every 16 nucleons (2 neutrons and 14 protons), 4 of these (25%) combined into one helium-4 nucleus. One analogy is to think of helium-4 as ash, and the amount of ash that one forms when one completely burns a piece of wood is insen ...
Stellar Evolution
... They don’t “evolve” but stay brown dwarfs and slowly fade over 100s of billions of years ...
... They don’t “evolve” but stay brown dwarfs and slowly fade over 100s of billions of years ...
Stellar Evolution
... They don’t “evolve” but stay brown dwarfs and slowly fade over 100s of billions of years ...
... They don’t “evolve” but stay brown dwarfs and slowly fade over 100s of billions of years ...
The Sun: Example of Radiation Laws
... High-mass stars (M > 8M⊙ ) evolve into both red and blue giants and supergiants as their cores burn heavier and heavier elements. ...
... High-mass stars (M > 8M⊙ ) evolve into both red and blue giants and supergiants as their cores burn heavier and heavier elements. ...
Introduction to the Big Bang Theory
... Play the movie backwards • If you could play the movie backwards, what would the objects be doing?_______________________________ _____________________________________________ _____________________________________________ _____________________________________________ • Following that thought back t ...
... Play the movie backwards • If you could play the movie backwards, what would the objects be doing?_______________________________ _____________________________________________ _____________________________________________ _____________________________________________ • Following that thought back t ...
Slide 1
... growth indicates the Earth's climatic environment over time • Unlike the other types of supernovae, Type Ia supernovae are generally found in all types of galaxies, including ellipticals. ...
... growth indicates the Earth's climatic environment over time • Unlike the other types of supernovae, Type Ia supernovae are generally found in all types of galaxies, including ellipticals. ...
s-process
... Significant production of r-process elements began when the metallicity of the Galaxy reached [Fe/H] = -3. The heavy n-capture elements were formed predominantly by the r-process at metallicities below [Fe/H] = -2.1. Elements from the s-process appear at a metallicity of [Fe/H] = -2.1, when low-mass ...
... Significant production of r-process elements began when the metallicity of the Galaxy reached [Fe/H] = -3. The heavy n-capture elements were formed predominantly by the r-process at metallicities below [Fe/H] = -2.1. Elements from the s-process appear at a metallicity of [Fe/H] = -2.1, when low-mass ...
species which remained immutable and unchanged thereafter. An
... of nuclear structure and the origin of the nuclear species. Cockcroft and Walton duplicated Rutherford's results using protons accelerated to moderate energies. Urey discovered the deuteron, Chadwick discovered the neutron, and neutrons were soon produced by accelerated deuterons in the laboratory b ...
... of nuclear structure and the origin of the nuclear species. Cockcroft and Walton duplicated Rutherford's results using protons accelerated to moderate energies. Urey discovered the deuteron, Chadwick discovered the neutron, and neutrons were soon produced by accelerated deuterons in the laboratory b ...
here - The Planetary Chemistry Laboratory
... On the red giant branches: He to C for ~110 million years No more nucleosynthesis, white dwarfs Massive stars above ~ 8 times the Sun’s mass e.g., 15 solar-mass star: main sequence: H to He for ~ 8 million years ...
... On the red giant branches: He to C for ~110 million years No more nucleosynthesis, white dwarfs Massive stars above ~ 8 times the Sun’s mass e.g., 15 solar-mass star: main sequence: H to He for ~ 8 million years ...
Light n-Capture Element Abundances in Metal
... scatter can be an indicator of more common sources for production of the n-capture elements are contributing to the elemental abundances. The turn-on time of these events will eliminate certain objects, such as low mass stars, as potential early contributors to the r-process. The abundances of Y and ...
... scatter can be an indicator of more common sources for production of the n-capture elements are contributing to the elemental abundances. The turn-on time of these events will eliminate certain objects, such as low mass stars, as potential early contributors to the r-process. The abundances of Y and ...
Cosmic Connection to the elements
... production of elements in stars in this range is similar, and these stars share a similar fate. They begin by fusing hydrogen into helium in their cores. This process continues for billions of years, until there is no longer enough hydrogen in the star’s core to fuse more helium. Without the energy ...
... production of elements in stars in this range is similar, and these stars share a similar fate. They begin by fusing hydrogen into helium in their cores. This process continues for billions of years, until there is no longer enough hydrogen in the star’s core to fuse more helium. Without the energy ...
The Interior Structure of Neutron Stars
... Beyond Neutron Drip & Complications Neutron drip proceeds from ρdrip=(4.3)(1014)kg/m3 until all nuclei have dripped free of nuclei by ρnuclear=(2.7)(1017)kg/m3 At very slightly higher densities we reach the muon Fermi energy and these will be created & we have neutron fluid + proton fluid + electro ...
... Beyond Neutron Drip & Complications Neutron drip proceeds from ρdrip=(4.3)(1014)kg/m3 until all nuclei have dripped free of nuclei by ρnuclear=(2.7)(1017)kg/m3 At very slightly higher densities we reach the muon Fermi energy and these will be created & we have neutron fluid + proton fluid + electro ...
Life Cycle of STARS
... • Are stars BORN??? • Take a moment to think about our own Sun, and write down an idea about how it was formed using what we have learned so far. ...
... • Are stars BORN??? • Take a moment to think about our own Sun, and write down an idea about how it was formed using what we have learned so far. ...
AS2001 - University of St Andrews
... low-Z stars. No Pop III (Z=0) stars seen (were they all high mass?). Infall of Z = 0 material causes Z => y. Z » min [ y, y ln(1/ m )] ...
... low-Z stars. No Pop III (Z=0) stars seen (were they all high mass?). Infall of Z = 0 material causes Z => y. Z » min [ y, y ln(1/ m )] ...
Week 12, Lecture 2 – Nuclear Synthesis
... -‐-‐ Nuclear Synthesis -‐-‐-‐ Big Bang -‐-‐-‐ Stellar processes -‐-‐-‐-‐ simple proton burning -‐-‐-‐-‐ cataly
... -‐-‐ Nuclear Synthesis -‐-‐-‐ Big Bang -‐-‐-‐ Stellar processes -‐-‐-‐-‐ simple proton burning -‐-‐-‐-‐ cataly
Introduction: The Night Sky
... neutron star is about 50% more massive than Sun, but is only 20 km across basically a gigantic atomic nucleus: protons and electrons have combined to form neutrons in extreme cases even this may not be stable, and a black hole is formed instead ...
... neutron star is about 50% more massive than Sun, but is only 20 km across basically a gigantic atomic nucleus: protons and electrons have combined to form neutrons in extreme cases even this may not be stable, and a black hole is formed instead ...
The light curves for a nova look like the following.
... basic predictions of the core-bounce picture (although with good data, many details still remain murky). ...
... basic predictions of the core-bounce picture (although with good data, many details still remain murky). ...
AS2001
... form 2D, then 4He. Yp set by p/n ratio, as virtually all n go into 4He leaving residual p as H. • Recombination: H and He nuclei capture free electrons. Universe now transparent to photons. ...
... form 2D, then 4He. Yp set by p/n ratio, as virtually all n go into 4He leaving residual p as H. • Recombination: H and He nuclei capture free electrons. Universe now transparent to photons. ...
Origin_of_Elements in the stars
... hydrogen and helium and their isotopes, and for very important reasons. Hydrogen is the simplest possible atom by definition, one proton and one electron. Anything less and it is no longer an atom; it is a subatomic particle with very different properties from the energetically stable atom. With thi ...
... hydrogen and helium and their isotopes, and for very important reasons. Hydrogen is the simplest possible atom by definition, one proton and one electron. Anything less and it is no longer an atom; it is a subatomic particle with very different properties from the energetically stable atom. With thi ...
Solution to Problem Set 1 1. The total number of nucleons in one
... naked eye, 6 = 4.7 + 5 log 10 pc , which gives d = 18.2 pc. The flux is then f = L/(4πd2 ) = 9.6 × 10−11 W m−2 . Assuming the area of the eyes is about A = 1 cm2 , then the total energy received in a time period of t = 1s is E = f At = 9.6 × 10−15 J. The photons are mostly in the visible range, so h ...
... naked eye, 6 = 4.7 + 5 log 10 pc , which gives d = 18.2 pc. The flux is then f = L/(4πd2 ) = 9.6 × 10−11 W m−2 . Assuming the area of the eyes is about A = 1 cm2 , then the total energy received in a time period of t = 1s is E = f At = 9.6 × 10−15 J. The photons are mostly in the visible range, so h ...
The Evolution of Elements
... the temperature of their cores, allowing different fusions to occur. When stars like our sun are about to die, they go through a red giant stage. Elements crucial for life such as oxygen and carbon are produced: ( γ = gamma rays) He+ 24He→ 48 Be ...
... the temperature of their cores, allowing different fusions to occur. When stars like our sun are about to die, they go through a red giant stage. Elements crucial for life such as oxygen and carbon are produced: ( γ = gamma rays) He+ 24He→ 48 Be ...
Study Notes for Chapter 30: Stars, Galaxies, and the Universe
... 7. A white dwarf is a hot, extremely dense core of matter left after a star collapses. 8. About 6,000 stars are visible from Earth without a telescope. 9. Absolute magnitude is the true brightness of a star. 10. After its temperature rises to 10,000,000°C, a protostar becomes a star when nuclear fus ...
... 7. A white dwarf is a hot, extremely dense core of matter left after a star collapses. 8. About 6,000 stars are visible from Earth without a telescope. 9. Absolute magnitude is the true brightness of a star. 10. After its temperature rises to 10,000,000°C, a protostar becomes a star when nuclear fus ...
Nucleosynthesis
Nucleosynthesis is the process that creates new atomic nuclei from pre-existing nucleons, primarily protons and neutrons. The first nuclei were formed about three minutes after the Big Bang, through the process called Big Bang nucleosynthesis. It was then that hydrogen and helium formed to become the content of the first stars, and this primeval process is responsible for the present hydrogen/helium ratio of the cosmos.With the formation of stars, heavier nuclei were created from hydrogen and helium by stellar nucleosynthesis, a process that continues today. Some of these elements, particularly those lighter than iron, continue to be delivered to the interstellar medium when low mass stars eject their outer envelope before they collapse to form white dwarfs. The remains of their ejected mass form the planetary nebulae observable throughout our galaxy.Supernova nucleosynthesis within exploding stars by fusing carbon and oxygen is responsible for the abundances of elements between magnesium (atomic number 12) and nickel (atomic number 28). Supernova nucleosynthesis is also thought to be responsible for the creation of rarer elements heavier than iron and nickel, in the last few seconds of a type II supernova event. The synthesis of these heavier elements absorbs energy (endothermic) as they are created, from the energy produced during the supernova explosion. Some of those elements are created from the absorption of multiple neutrons (the R process) in the period of a few seconds during the explosion. The elements formed in supernovas include the heaviest elements known, such as the long-lived elements uranium and thorium.Cosmic ray spallation, caused when cosmic rays impact the interstellar medium and fragment larger atomic species, is a significant source of the lighter nuclei, particularly 3He, 9Be and 10,11B, that are not created by stellar nucleosynthesis.In addition to the fusion processes responsible for the growing abundances of elements in the universe, a few minor natural processes continue to produce very small numbers of new nuclides on Earth. These nuclides contribute little to their abundances, but may account for the presence of specific new nuclei. These nuclides are produced via radiogenesis (decay) of long-lived, heavy, primordial radionuclides such as uranium and thorium. Cosmic ray bombardment of elements on Earth also contribute to the presence of rare, short-lived atomic species called cosmogenic nuclides.