Solutions to HW 1-2
... magnetic monopoles, which have never been observed. These monopoles may have been dispersed over very large distances during inflation, reducing their abundance in the Universe to an extent that they are not detectable by our current experiments. Structure formation: inflation may also explain the f ...
... magnetic monopoles, which have never been observed. These monopoles may have been dispersed over very large distances during inflation, reducing their abundance in the Universe to an extent that they are not detectable by our current experiments. Structure formation: inflation may also explain the f ...
When Stars Go Boom
... Students of almost all ages have some awareness of the nighttime stars, and many are aware of the fact that the Sun is one such star. Because we do not see obvious changes in stars on timescales of days or even years, most students don’t give much thought to the question of how long stars last, and ...
... Students of almost all ages have some awareness of the nighttime stars, and many are aware of the fact that the Sun is one such star. Because we do not see obvious changes in stars on timescales of days or even years, most students don’t give much thought to the question of how long stars last, and ...
5Stars_Part_Two
... How do we know all this? By observing Globular clusters… 1. Globular clusters are thousands of stars that all formed at more or less the same time. 2. Globular clusters are much smaller than galaxies. 3. Galaxies create stars in an on-going process. 4. The stars in a globular cluster accrete sudde ...
... How do we know all this? By observing Globular clusters… 1. Globular clusters are thousands of stars that all formed at more or less the same time. 2. Globular clusters are much smaller than galaxies. 3. Galaxies create stars in an on-going process. 4. The stars in a globular cluster accrete sudde ...
Chapter 10
... nucleus of our Galaxy, and what is the probable explanation? 7. Describe the factors involved in galactic formation, including the role of collisions between galaxies. 8. Be able to identify a galaxy by its shape, according to the Hubble sequence. 9. Compare and contrast elliptical galaxies and spir ...
... nucleus of our Galaxy, and what is the probable explanation? 7. Describe the factors involved in galactic formation, including the role of collisions between galaxies. 8. Be able to identify a galaxy by its shape, according to the Hubble sequence. 9. Compare and contrast elliptical galaxies and spir ...
Scientists confirm most distant galaxy ever
... every year. The z8_GND_5296 galaxy converts hydrogen in the amount of 300 times the mass of our sun into new stars each year. By contrast, the Milky Way only produces stars at one or two solar masses per year. Scientists established through previous research that in the first billion years of the un ...
... every year. The z8_GND_5296 galaxy converts hydrogen in the amount of 300 times the mass of our sun into new stars each year. By contrast, the Milky Way only produces stars at one or two solar masses per year. Scientists established through previous research that in the first billion years of the un ...
Monday, Oct. 20
... A Red Giant with helium fusion When helium fusion starts generating energy in the core of a red giant, the core expands and hydrogen fusion in the shell around the core slows down. As a result, less total energy is being generated, and the envelope contracts and warms up some. But pretty soon all o ...
... A Red Giant with helium fusion When helium fusion starts generating energy in the core of a red giant, the core expands and hydrogen fusion in the shell around the core slows down. As a result, less total energy is being generated, and the envelope contracts and warms up some. But pretty soon all o ...
How do we know what stars are
... Life Cycle of Stars Video https://www.youtube.com/watch?v=mzE7VZMT1z8 Age of a star is determined by the emission spectrum and the percentage of heavier elements. A star begins its life composed of _______________. Fusion creates ____________ in the core which increases as the star ages. When helium ...
... Life Cycle of Stars Video https://www.youtube.com/watch?v=mzE7VZMT1z8 Age of a star is determined by the emission spectrum and the percentage of heavier elements. A star begins its life composed of _______________. Fusion creates ____________ in the core which increases as the star ages. When helium ...
Stellar Evolution - users.monash.edu.au
... Constraints from Li abundances? Pilachowski et al 2000 ...
... Constraints from Li abundances? Pilachowski et al 2000 ...
To understand the deaths of stars and how it depends on
... • Slow: you add 1 neutron at a time and wait. If you add too many neutrons to an atom 1 neutron will turn into a proton and you suddenly have a different atom. • Fast: you add them all at once. Then some neutrons convert to protons. • These methods create different atoms and/or isotopes. • However, ...
... • Slow: you add 1 neutron at a time and wait. If you add too many neutrons to an atom 1 neutron will turn into a proton and you suddenly have a different atom. • Fast: you add them all at once. Then some neutrons convert to protons. • These methods create different atoms and/or isotopes. • However, ...
The Primordial Abundance of $^ 6$ Li and $^ 9$ be
... bluest point of the turnoff (SLN93). However, the effective temperature of this star is too low for it to be a massive main sequence star. Stellar models with the metallicity of HD 84937 typically have turn-off temperatures ranging from 6700 K (age 14 Gyr) to 6540 K (age 18 Gyr). SLN93 suggest that ...
... bluest point of the turnoff (SLN93). However, the effective temperature of this star is too low for it to be a massive main sequence star. Stellar models with the metallicity of HD 84937 typically have turn-off temperatures ranging from 6700 K (age 14 Gyr) to 6540 K (age 18 Gyr). SLN93 suggest that ...
Post-AGB stars in the Magellanic Clouds and neutron
... we artificially introduced a given abundance Yp of protons at the deepest extent of each TDU episode, which led to the formation of the 13 C pocket. Table 1 shows the main features of the 13 C-pocket models where Yp is the proton abundance, MPMZ is the mass extent of the p-rich region, and Mptot the ...
... we artificially introduced a given abundance Yp of protons at the deepest extent of each TDU episode, which led to the formation of the 13 C pocket. Table 1 shows the main features of the 13 C-pocket models where Yp is the proton abundance, MPMZ is the mass extent of the p-rich region, and Mptot the ...
ppt document
... The sun is mostly hydrogen as are all stars. It has a relatively high concentration of helium since that is what it is burning hydrogen into. The amount of helium and the other elements and the age of the earth (thought to be the same as the sun’s) indicate that the sun is about 4.5 billion years ol ...
... The sun is mostly hydrogen as are all stars. It has a relatively high concentration of helium since that is what it is burning hydrogen into. The amount of helium and the other elements and the age of the earth (thought to be the same as the sun’s) indicate that the sun is about 4.5 billion years ol ...
The Main Sequence
... • For neutron stars, maximum mass ~3Msun • What happens if a high-mass star is SO big that its central core is bigger than this? • What happens when gravity is stronger than even neutron degeneracy pressure? ...
... • For neutron stars, maximum mass ~3Msun • What happens if a high-mass star is SO big that its central core is bigger than this? • What happens when gravity is stronger than even neutron degeneracy pressure? ...
powerpoint
... • Slow: you add 1 neutron at a time and wait. If you add too many neutrons to an atom 1 neutron will turn into a proton and you suddenly have a different atom. • Fast: you add them all at once. Then some neutrons convert to protons. • These methods create different atoms and/or isotopes. • However, ...
... • Slow: you add 1 neutron at a time and wait. If you add too many neutrons to an atom 1 neutron will turn into a proton and you suddenly have a different atom. • Fast: you add them all at once. Then some neutrons convert to protons. • These methods create different atoms and/or isotopes. • However, ...
30-1
... 6. What is the most common element in stars? What is the second most common element? _______________________________________________________________ ...
... 6. What is the most common element in stars? What is the second most common element? _______________________________________________________________ ...
Bolte_LRIS_08A
... VLT/FLAMES facility measured abundances for a large number of giants in the dSph galaxies Sculptor, Fornax, Sextans and Carina. Their results show that while there are large dSph-to-dSph differences in the metallicity distributions, which suggests a wide variety of star formation and chemical enrich ...
... VLT/FLAMES facility measured abundances for a large number of giants in the dSph galaxies Sculptor, Fornax, Sextans and Carina. Their results show that while there are large dSph-to-dSph differences in the metallicity distributions, which suggests a wide variety of star formation and chemical enrich ...
Radioactivity and Nuclear Physics
... Alpha decay is the emission of a helium nucleus, causing the product to have an atomic number 2 less than the original and an atomic mass number 4 less than the original. Beta minus decay is the emission of an electron, causing the product to have an atomic number 1 greater than the original Beta pl ...
... Alpha decay is the emission of a helium nucleus, causing the product to have an atomic number 2 less than the original and an atomic mass number 4 less than the original. Beta minus decay is the emission of an electron, causing the product to have an atomic number 1 greater than the original Beta pl ...
The Magic of Star Dust - Exploring Exotic Nuclei
... both positively charged nucleons called ‘protons’ and electrically neutral ones called ‘neutrons’. As the universe cooled and expanded the hadrons coalesced together to form more complex objects, that we refer to as nuclei. Nuclei form the core of all matter around us and constitute more than 99% of ...
... both positively charged nucleons called ‘protons’ and electrically neutral ones called ‘neutrons’. As the universe cooled and expanded the hadrons coalesced together to form more complex objects, that we refer to as nuclei. Nuclei form the core of all matter around us and constitute more than 99% of ...
Observational Overview
... fixed/unchanging. (Made them famous – awarded money to continue their work.) Tycho – 1572; Kepler – 1604; next 1987. If the mass of the core ≥ 3 M (M∗ ∼ 20 M ), nothing can stop the collapse of the core and a black hole is formed. Supernovae are important because the explosion produces many “rare” ...
... fixed/unchanging. (Made them famous – awarded money to continue their work.) Tycho – 1572; Kepler – 1604; next 1987. If the mass of the core ≥ 3 M (M∗ ∼ 20 M ), nothing can stop the collapse of the core and a black hole is formed. Supernovae are important because the explosion produces many “rare” ...
Session 3 – The Big Bang Pt.2
... someone else), the intense gravity from all that concentrated matter would cause it to be deep in a black hole, out of which the matter should not be able to emerge. Back-ofenvelope calculations supported his point. If our understanding of the implications of the big bang were right, it could never ...
... someone else), the intense gravity from all that concentrated matter would cause it to be deep in a black hole, out of which the matter should not be able to emerge. Back-ofenvelope calculations supported his point. If our understanding of the implications of the big bang were right, it could never ...
Exploring the Helium Reionization Era
... cooled to the point where the electrons could combine with protons to form atoms of hydrogen and other light elements. Following this transition, called Recombination, photons were not as scattered and the universe became transparent. Ironically, the period immediately after Recombination is referre ...
... cooled to the point where the electrons could combine with protons to form atoms of hydrogen and other light elements. Following this transition, called Recombination, photons were not as scattered and the universe became transparent. Ironically, the period immediately after Recombination is referre ...
The Sizes of Stars
... When all the hydrogen in a stellar core is changed to helium, there is no more energy to hold it up. Gravity takes over and the core contracts. This produces energy. In the area right surrounding the core, there is plenty of hydrogen. The pressure in this area increases (since contraction increases ...
... When all the hydrogen in a stellar core is changed to helium, there is no more energy to hold it up. Gravity takes over and the core contracts. This produces energy. In the area right surrounding the core, there is plenty of hydrogen. The pressure in this area increases (since contraction increases ...
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.