Chapter 7 Neutron Stars - Ira-Inaf
... gravitational potential energy of an electron at the surface of such a star would be less than 0.1% its rest mass energy. This tells us that general relativistic effects are not important to white dwarf physics. 7.2 Neutron stars The above discussion points out the the final state of a star that has ...
... gravitational potential energy of an electron at the surface of such a star would be less than 0.1% its rest mass energy. This tells us that general relativistic effects are not important to white dwarf physics. 7.2 Neutron stars The above discussion points out the the final state of a star that has ...
Metal-poor Stars
... lower limit for the age of the Universe. This fortuitously also provides the opportunity of bringing together astrophysics and nuclear physics because these objects act as a “cosmic lab” for both fields of study. Most suitable for such age measurements are cool metal-poor giants that exhibit strong ...
... lower limit for the age of the Universe. This fortuitously also provides the opportunity of bringing together astrophysics and nuclear physics because these objects act as a “cosmic lab” for both fields of study. Most suitable for such age measurements are cool metal-poor giants that exhibit strong ...
Seating Chart for Final Exam PHOTO ID REQUIRED! SIT IN YOUR ASSIGNED ROW!
... Slide 1: Disk=circular orbits approximately in plane of disk; Bulge and Halo = elongated orbits going off in all directions. Milky Way = Sb (or maybe an SBb). See textbook [15.1] for Hubble classification scheme. Slide 2: Stars convert HHe, then HeC and on up through Iron in their cores, then recy ...
... Slide 1: Disk=circular orbits approximately in plane of disk; Bulge and Halo = elongated orbits going off in all directions. Milky Way = Sb (or maybe an SBb). See textbook [15.1] for Hubble classification scheme. Slide 2: Stars convert HHe, then HeC and on up through Iron in their cores, then recy ...
The First Stars in the Universe - Scientific American
... and Abraham Loeb of Harvard, one of us (Bromm) devised theoretical models of such stars with masses between 100 and 1,000 solar masses. The models showed that the stars had surface temperatures of about 100,000 kelvins—about 17 times higher than the sun’s surface temperature. Therefore, the first st ...
... and Abraham Loeb of Harvard, one of us (Bromm) devised theoretical models of such stars with masses between 100 and 1,000 solar masses. The models showed that the stars had surface temperatures of about 100,000 kelvins—about 17 times higher than the sun’s surface temperature. Therefore, the first st ...
Final exam solutions - University of Rochester
... _____ Nuclear fission is the power source for stars. _____ Most of the uranium in the universe was made during the first several minutes after the big bang. _____ Some scientists claim that new universes might be spawned inside black holes. _____ The existence of dark matter is needed to account for ...
... _____ Nuclear fission is the power source for stars. _____ Most of the uranium in the universe was made during the first several minutes after the big bang. _____ Some scientists claim that new universes might be spawned inside black holes. _____ The existence of dark matter is needed to account for ...
Physica 133-11f: Sample Final Exam Here are sample questions for
... A) Before that time, the gas in the universe was dense and ionized and thus did not allow light to travel freely. B) 380,000 years after the Big Bang marks the time when stars were first born, and thus began to shine the light by which we can see the universe. C) Before that time, the universe was d ...
... A) Before that time, the gas in the universe was dense and ionized and thus did not allow light to travel freely. B) 380,000 years after the Big Bang marks the time when stars were first born, and thus began to shine the light by which we can see the universe. C) Before that time, the universe was d ...
Salpeter Mass Function
... Comments on the Salpeter IMF What is the origin of the IMF? Most important unsolved problem in star formation. Many theories but no consensus. Observationally, known that dense cores in molecular clouds have a power-law mass function rather similar to the IMF. So the IMF may be determined in part b ...
... Comments on the Salpeter IMF What is the origin of the IMF? Most important unsolved problem in star formation. Many theories but no consensus. Observationally, known that dense cores in molecular clouds have a power-law mass function rather similar to the IMF. So the IMF may be determined in part b ...
Red giants aren`t just big, they`re turbulent
... Red giants are telltale signs of aging in stars. Like people, stars have lifecycles. They are born from interstellar clouds of gas that collapse under the pull of gravity. The extreme temperatures and pressures at the cores of these clouds fuse protons – hydrogen nuclei – into the nuclei of helium, ...
... Red giants are telltale signs of aging in stars. Like people, stars have lifecycles. They are born from interstellar clouds of gas that collapse under the pull of gravity. The extreme temperatures and pressures at the cores of these clouds fuse protons – hydrogen nuclei – into the nuclei of helium, ...
The Milky Way - Chandra X
... matter that cannot be seen with any type of telescope, but is detected by its gravitational effects. Studies of the motions of stars and gas in the Milky Way indicate that the mass of the dark matter halo is about twenty times greater than the mass of all the stars in the galaxy. It is thought that ...
... matter that cannot be seen with any type of telescope, but is detected by its gravitational effects. Studies of the motions of stars and gas in the Milky Way indicate that the mass of the dark matter halo is about twenty times greater than the mass of all the stars in the galaxy. It is thought that ...
The Milky Way - Chandra X
... matter that cannot be seen with any type of telescope, but is detected by its gravitational effects. Studies of the motions of stars and gas in the Milky Way indicate that the mass of the dark matter halo is about twenty times greater than the mass of all the stars in the galaxy. It is thought that ...
... matter that cannot be seen with any type of telescope, but is detected by its gravitational effects. Studies of the motions of stars and gas in the Milky Way indicate that the mass of the dark matter halo is about twenty times greater than the mass of all the stars in the galaxy. It is thought that ...
Please read the following excerpt from an editorial about the Atkins
... Please read each passage carefully and rate how difficult it was to read on the 6 point scale. You will be given 13 minutes to read them. Later you will be asked several questions about each passage. Supernova Supernovae are stupendous explosions that destroy an entire star. The "nova" ("new") part ...
... Please read each passage carefully and rate how difficult it was to read on the 6 point scale. You will be given 13 minutes to read them. Later you will be asked several questions about each passage. Supernova Supernovae are stupendous explosions that destroy an entire star. The "nova" ("new") part ...
A Simple Model for r-Process Scatter and Halo Evolution
... 3. The placement of a star between these extremes quantifies a admixture of nucleosynthesis sources recorded in the star. Thus, (a) at the very earliest times, when single SN events are really all that contaminate a given star, the r/Fe scatter should only populate the extremes. (b) At later times, ...
... 3. The placement of a star between these extremes quantifies a admixture of nucleosynthesis sources recorded in the star. Thus, (a) at the very earliest times, when single SN events are really all that contaminate a given star, the r/Fe scatter should only populate the extremes. (b) At later times, ...
Stellar Clusters and Star Formation:
... namely a ball of gas collapsed under its own self-gravity until it’s stabilized by sufficient internal pressure. At that point it is a hydrogen fusing main sequence star. However, over the last 25 years we have learned and observed that the actual process of the formation individual stars of conside ...
... namely a ball of gas collapsed under its own self-gravity until it’s stabilized by sufficient internal pressure. At that point it is a hydrogen fusing main sequence star. However, over the last 25 years we have learned and observed that the actual process of the formation individual stars of conside ...
Stars as thermonuclear reactors: their fuels and ashes
... the Big Bang, contains many more photons per particle of matter with mass, e.g. electrons, protons and neutrons. Because of the high entropy and the consequent low density of matter (on terrestrial or stellar scales) at any given temperature as the universe expanded, there was time to manufacture el ...
... the Big Bang, contains many more photons per particle of matter with mass, e.g. electrons, protons and neutrons. Because of the high entropy and the consequent low density of matter (on terrestrial or stellar scales) at any given temperature as the universe expanded, there was time to manufacture el ...
Cosmology with objects from the Hamburg Quasar Surveys
... measurement of the primordial deuterium abundance therefore gives the cosmic baryon density Щb. A natural place to look for primordial abundances is in high-redshift, low metal abundance intergalactic clouds where there is little contamination with processed matter ejected by stars where D is destro ...
... measurement of the primordial deuterium abundance therefore gives the cosmic baryon density Щb. A natural place to look for primordial abundances is in high-redshift, low metal abundance intergalactic clouds where there is little contamination with processed matter ejected by stars where D is destro ...
New Scientist - Quark Nova Project
... have lower net energy and hence be more stable than nuclear matter made of protons and neutrons. ...
... have lower net energy and hence be more stable than nuclear matter made of protons and neutrons. ...
Nuclear Astrophysics
... Let’s consider this a working “hypothesis” for now. And let us see if it makes sense when we consider what we’ve just learned from the CNO1,2 formalism along with what the astronomical observations reveal.. • Helium (alpha) burning core. • Shell outside core burning CNO-cycle • Convective outer enve ...
... Let’s consider this a working “hypothesis” for now. And let us see if it makes sense when we consider what we’ve just learned from the CNO1,2 formalism along with what the astronomical observations reveal.. • Helium (alpha) burning core. • Shell outside core burning CNO-cycle • Convective outer enve ...
COSMIC RAY ACCELERATION and TRANSPORT LECTURE I
... From the previous plot we see that at low energies P/S ~ 0.1 which implies X(E) ~ 5 g cm-2 As a function of energy: ...
... From the previous plot we see that at low energies P/S ~ 0.1 which implies X(E) ~ 5 g cm-2 As a function of energy: ...
Stellar Luminosity and Mass Functions * * * * * History and
... Massive stars have short lifetimes Suppose we observe the luminosity function of an old cluster. There are no very luminous main sequence stars. But this does not mean that the IMF of the cluster had zero massive stars, only that such stars have ended their main sequence lifetimes. More generally, ...
... Massive stars have short lifetimes Suppose we observe the luminosity function of an old cluster. There are no very luminous main sequence stars. But this does not mean that the IMF of the cluster had zero massive stars, only that such stars have ended their main sequence lifetimes. More generally, ...
Potassium abundances in nearby metal-poor stars
... Aims. The potassium abundances for 58 metal-poor stars are determined using high-resolution spectroscopy. The abundance trends in stars of different population are discussed. Methods. All abundance results have been derived from NLTE statistical equilibrium calculations and spectrum synthesis methods ...
... Aims. The potassium abundances for 58 metal-poor stars are determined using high-resolution spectroscopy. The abundance trends in stars of different population are discussed. Methods. All abundance results have been derived from NLTE statistical equilibrium calculations and spectrum synthesis methods ...
Readings for Prof. Michael J. Crowe`s Two Sessions on The
... Origins site says: “600,000,000 years after the big bang: Within galaxies, as stars were being born, others died...often in enormous cataclysmic explosions. These explosions, called supernovae, are important to the evolution of galaxies because they distribute all the common elements such as oxygen, ...
... Origins site says: “600,000,000 years after the big bang: Within galaxies, as stars were being born, others died...often in enormous cataclysmic explosions. These explosions, called supernovae, are important to the evolution of galaxies because they distribute all the common elements such as oxygen, ...
Life Cycle of a Star
... After the incredible release of energy from the SUPERNOVA a dense core (1 trillion times denser than a white dwarf) is all that remains of the Massive Star. If the mass is too dense it will continue to collapse on itself forming a black hole. The gravitational pull of a black hole is so great, light ...
... After the incredible release of energy from the SUPERNOVA a dense core (1 trillion times denser than a white dwarf) is all that remains of the Massive Star. If the mass is too dense it will continue to collapse on itself forming a black hole. The gravitational pull of a black hole is so great, light ...
ISP 205 Final Exam Seating Chart SIT IN CORRECT ROW
... Slide 1: Disk=circular orbits approximately in plane of disk; Bulge and Halo = elongated orbits going off in all directions. Milky Way = Sb (or maybe an SBb). See textbook [15.1] for Hubble classification scheme. Slide 2: Stars convert HHe, then HeC and on up through Iron in their cores, then recy ...
... Slide 1: Disk=circular orbits approximately in plane of disk; Bulge and Halo = elongated orbits going off in all directions. Milky Way = Sb (or maybe an SBb). See textbook [15.1] for Hubble classification scheme. Slide 2: Stars convert HHe, then HeC and on up through Iron in their cores, then recy ...
www.astro.caltech.edu
... Absorption spectra of GRBs do much more than tell us the distance of the burst – they also reveal the chemical composition and physical conditions of the galaxy in which the burst happened. The light from the GRB passes through gas and dust in its host galaxy, which leave absorption-line imprints th ...
... Absorption spectra of GRBs do much more than tell us the distance of the burst – they also reveal the chemical composition and physical conditions of the galaxy in which the burst happened. The light from the GRB passes through gas and dust in its host galaxy, which leave absorption-line imprints th ...
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.