Basics of chemical evolution
... Chemical evolution • The metal abundance of the gas, and of subsequent generations of stars, should increase in time. – if there is no gas infall from the outside ...
... Chemical evolution • The metal abundance of the gas, and of subsequent generations of stars, should increase in time. – if there is no gas infall from the outside ...
The Sun is a Plasma Diffuser that Sorts Atoms by Mass*
... supernova (SN) likely produced these nuclides. Two of them, 244 Pu and 60 Fe, could only have been made in an SN [22]. Decay products of extinct 244 Pu and 129 I have also been identified in the Earth [23]. By 1961, Fowler et al. [24] had noted that the levels of short-lived radioactivity were higher ...
... supernova (SN) likely produced these nuclides. Two of them, 244 Pu and 60 Fe, could only have been made in an SN [22]. Decay products of extinct 244 Pu and 129 I have also been identified in the Earth [23]. By 1961, Fowler et al. [24] had noted that the levels of short-lived radioactivity were higher ...
The Milky Way
... • Cloud is very cold (10-30 K) • Stellar winds prevent rest of cloud from forming stars ...
... • Cloud is very cold (10-30 K) • Stellar winds prevent rest of cloud from forming stars ...
The Life Cycles of Stars, Part I
... has nothing left to fuse (because of iron's nuclear structure, it does not permit its atoms to fuse into heavier elements) and fusion ceases. In less than a second, the star begins the final phase of its gravitational collapse. The core temperature rises to over 100 billion degrees as the iron atoms ...
... has nothing left to fuse (because of iron's nuclear structure, it does not permit its atoms to fuse into heavier elements) and fusion ceases. In less than a second, the star begins the final phase of its gravitational collapse. The core temperature rises to over 100 billion degrees as the iron atoms ...
Answers to Coursebook questions – Chapter E4
... be seen or easily detected. This is divided between WIMPS and MACHOS. WIMPS (massive weakly interacting particles) may include neutrinos and exotic particles predicted by models of particle physics e.g. supersymmetric particles. These have masses similar to those of atomic nuclei and interact via th ...
... be seen or easily detected. This is divided between WIMPS and MACHOS. WIMPS (massive weakly interacting particles) may include neutrinos and exotic particles predicted by models of particle physics e.g. supersymmetric particles. These have masses similar to those of atomic nuclei and interact via th ...
closed-box model
... In galaxies, gas is transformed into stars. Each star burns H and He in its nucleus and produces heavy elements. These elements are partially returned into the interstellar gas at the end of the star's life, through winds and supernovae explosions. Some fraction of the metals are locked into the rem ...
... In galaxies, gas is transformed into stars. Each star burns H and He in its nucleus and produces heavy elements. These elements are partially returned into the interstellar gas at the end of the star's life, through winds and supernovae explosions. Some fraction of the metals are locked into the rem ...
Stellar Death Final Phases
... White dwarfs are simple structures because the pressure that supports them is supplied almost entirely by degenerate electrons. In a white dwarf, the electrons are completely degenerate throughout the star, except for a very thin layer at the surface. A White Dwarf is the “naked” electron-degenerate ...
... White dwarfs are simple structures because the pressure that supports them is supplied almost entirely by degenerate electrons. In a white dwarf, the electrons are completely degenerate throughout the star, except for a very thin layer at the surface. A White Dwarf is the “naked” electron-degenerate ...
Life Stages of High
... carbon in a shell around the carbon core, and H fuses to He in a shell around the helium layer. • This double-shell-burning stage never reaches equilibrium—the fusion rate periodically spikes upward in a series of thermal pulses. • With each spike, convection dredges carbon up from the core and tran ...
... carbon in a shell around the carbon core, and H fuses to He in a shell around the helium layer. • This double-shell-burning stage never reaches equilibrium—the fusion rate periodically spikes upward in a series of thermal pulses. • With each spike, convection dredges carbon up from the core and tran ...
This is a preview of the published version of the quiz
... not slowing down but is rather speeding up, or accelerating in its expansion, used a standard candle that you should be familiar with by now. What did they use? ...
... not slowing down but is rather speeding up, or accelerating in its expansion, used a standard candle that you should be familiar with by now. What did they use? ...
Chapter 3: the Sun - University of Waterloo
... • Stars are born from this gas and dust, collectively known as the interstellar medium. • During their lifetime, stars may return some material to the ISM through surface winds or explosive events • In supernova explosions, most of the star is dispersed throughout the ISM. ...
... • Stars are born from this gas and dust, collectively known as the interstellar medium. • During their lifetime, stars may return some material to the ISM through surface winds or explosive events • In supernova explosions, most of the star is dispersed throughout the ISM. ...
Stellar Structure and Evolution II
... carbon in a shell around the carbon core, and H fuses to He in a shell around the helium layer • This double-shell burning stage never reaches equilibrium—fusion rate periodically spikes upward in a series of thermal pulses • With each spike, convection dredges carbon up from core and transports it ...
... carbon in a shell around the carbon core, and H fuses to He in a shell around the helium layer • This double-shell burning stage never reaches equilibrium—fusion rate periodically spikes upward in a series of thermal pulses • With each spike, convection dredges carbon up from core and transports it ...
NASA`s Chandra Sees Brightest Supernova Ever
... mass of order 100 M⊙ or more. A heavy H envelope might help explain the unusually slow speed of only about 4000 km s−1 indicated by the H line, and might provide a natural explanation for the long duration and rise time of the SN because of time needed for energy to diffuse out of the massive envelo ...
... mass of order 100 M⊙ or more. A heavy H envelope might help explain the unusually slow speed of only about 4000 km s−1 indicated by the H line, and might provide a natural explanation for the long duration and rise time of the SN because of time needed for energy to diffuse out of the massive envelo ...
the formation of the earth
... and a few percent of all other elements. The heavier elements in the frigid cloud of dust and gases were mostly silicon, aluminum, iron, and calcium. Oxygen, carbon, and nitrogen were also present in organic compounds. ...
... and a few percent of all other elements. The heavier elements in the frigid cloud of dust and gases were mostly silicon, aluminum, iron, and calcium. Oxygen, carbon, and nitrogen were also present in organic compounds. ...
Star Life
... 8) The smallest of stars will end their life as which of the following? a. Black Hole b. White Dwarf c. Super Red Giant d. Neutron Star 9) A main sequence star is mostly made of which two elements? a. Hydrogen and Carbon b. Hydrogen and Helium c. Helium and Carbon d. Helium and Iron 10) Which stage ...
... 8) The smallest of stars will end their life as which of the following? a. Black Hole b. White Dwarf c. Super Red Giant d. Neutron Star 9) A main sequence star is mostly made of which two elements? a. Hydrogen and Carbon b. Hydrogen and Helium c. Helium and Carbon d. Helium and Iron 10) Which stage ...
Cosmology ppt. - University of Dayton
... together, radiation just expands with the universe to become the 2.7 K cosmic radiation of today. PClouds of matter condense out to form clumps of matter, galaxies, etc. Formation of galaxies needs dark matter? ...
... together, radiation just expands with the universe to become the 2.7 K cosmic radiation of today. PClouds of matter condense out to form clumps of matter, galaxies, etc. Formation of galaxies needs dark matter? ...
opportunities nuclear astrophysics
... Our understanding of these processes has developed greatly in the last 75 years. It was known early on that nuclear reactions must provide the energy for the sun. No other processes, chemical or gravitational, could yield the sun’s luminosity over its 4.6 billion-year life. More direct evidence for ...
... Our understanding of these processes has developed greatly in the last 75 years. It was known early on that nuclear reactions must provide the energy for the sun. No other processes, chemical or gravitational, could yield the sun’s luminosity over its 4.6 billion-year life. More direct evidence for ...
Written by G. Jeffrey Taylor
... ome presolar grains found in meteorites have isotopic compositions of silicon, carbon, and other elements predicted for formation in material flowing from asymptotic giant branch starts, nicknamed AGB stars. Stars with masses not too much different from the Sun reach this stage after using up all th ...
... ome presolar grains found in meteorites have isotopic compositions of silicon, carbon, and other elements predicted for formation in material flowing from asymptotic giant branch starts, nicknamed AGB stars. Stars with masses not too much different from the Sun reach this stage after using up all th ...
Dec. 6 - UF Physics
... was smaller yesterday than today, and so on until a “day that would not have had a yesterday”: the moment of creation. • This idea wasn’t widely accepted at first: Fred Hoyle dismissed “this hot Big Bang”, noting that there wasn’t any record or remnants. He argued for a “steady state” universe. ...
... was smaller yesterday than today, and so on until a “day that would not have had a yesterday”: the moment of creation. • This idea wasn’t widely accepted at first: Fred Hoyle dismissed “this hot Big Bang”, noting that there wasn’t any record or remnants. He argued for a “steady state” universe. ...
slides - CAASTRO
... How Big is the Universe? › This radiation tells Cosmologists how old, and so how big the Universe is › The observed Universe is 13 billion years old, so its size is 10s of billions of light-years › Compare with the Sun and Earth, which are 4.5 billion years old ...
... How Big is the Universe? › This radiation tells Cosmologists how old, and so how big the Universe is › The observed Universe is 13 billion years old, so its size is 10s of billions of light-years › Compare with the Sun and Earth, which are 4.5 billion years old ...
Institute for Structure and Nuclear Astrophysics
... Our understanding of these processes has developed greatly in the last 75 years. It was known early on that nuclear reactions must provide the energy for the sun. No other processes, chemical or gravitational, could yield the sun’s luminosity over its 4.6 billion-year life. More direct evidence for ...
... Our understanding of these processes has developed greatly in the last 75 years. It was known early on that nuclear reactions must provide the energy for the sun. No other processes, chemical or gravitational, could yield the sun’s luminosity over its 4.6 billion-year life. More direct evidence for ...
File
... spread out in an immense volume. All stars begin their lives as parts of nebulas. ______________ can pull some of the gas and dust in a nebula together. The contracting cloud is then called a _________________________. Proto means _______________ stage of a star’s life. A star is born when ...
... spread out in an immense volume. All stars begin their lives as parts of nebulas. ______________ can pull some of the gas and dust in a nebula together. The contracting cloud is then called a _________________________. Proto means _______________ stage of a star’s life. A star is born when ...
Stellar Evolution Game (PDF: 112k)
... 1. Teach students to read an HR diagram. Students will need to use this information to answer the questions during the game. 2. Students will also need to be knowledgeable about basic stellar evolution pathways for stars based on their masses. 3. Copy a set of the game cards on matching colored pape ...
... 1. Teach students to read an HR diagram. Students will need to use this information to answer the questions during the game. 2. Students will also need to be knowledgeable about basic stellar evolution pathways for stars based on their masses. 3. Copy a set of the game cards on matching colored pape ...
STAAR Science Tutorial 34 TEK 8.8A: Stars, Galaxies
... discussed in the next section on the Hertzsprung-Russell Diagram. Most stars are found in pairs (binary stars) or small multiple-star groups. Our own star, the Sun, is unusual in that it is not part of such a group. For a detailed description of our star the Sun, see Tutorial 35: The Sun. ...
... discussed in the next section on the Hertzsprung-Russell Diagram. Most stars are found in pairs (binary stars) or small multiple-star groups. Our own star, the Sun, is unusual in that it is not part of such a group. For a detailed description of our star the Sun, see Tutorial 35: The Sun. ...
STAAR Science Tutorial 28 TEK 8.8A: Stars
... discussed in the next section on the Hertzsprung-Russell Diagram. Most stars are found in pairs (binary stars) or small multiple-star groups. Our own star, the Sun, is unusual in that it is not part of such a group. For a detailed description of our star the Sun, see Tutorial 29: The Sun. ...
... discussed in the next section on the Hertzsprung-Russell Diagram. Most stars are found in pairs (binary stars) or small multiple-star groups. Our own star, the Sun, is unusual in that it is not part of such a group. For a detailed description of our star the Sun, see Tutorial 29: The Sun. ...
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.