GE: Friday morning *Cosmology and general relativity: the evolution
... If General Relativity holds true then the majority of the Universe’s matter is exotic and unknown. With current developments in theoretical physics, alternatives to Einstein’s theory have begun to emerge. Furthermore, the coming decade promises wide-ranging, cutting edge experiments on cosmic scales ...
... If General Relativity holds true then the majority of the Universe’s matter is exotic and unknown. With current developments in theoretical physics, alternatives to Einstein’s theory have begun to emerge. Furthermore, the coming decade promises wide-ranging, cutting edge experiments on cosmic scales ...
document
... What happens in a low-mass star when core temperature rises enough for helium fusion to begin? A. Helium fusion slowly starts up. B. Hydrogen fusion stops. C. Helium fusion rises very sharply. (Hint: Degeneracy pressure is the main form of pressure in the inert helium core.) ...
... What happens in a low-mass star when core temperature rises enough for helium fusion to begin? A. Helium fusion slowly starts up. B. Hydrogen fusion stops. C. Helium fusion rises very sharply. (Hint: Degeneracy pressure is the main form of pressure in the inert helium core.) ...
The surface composition of Beta Pictoris
... inferred by Paresce (1991) from Geneva photometry, a result that has prompted King and Patten (1992) to suggest that β Pic is a λ Boo star. We note that the HST GHRS data analyzed by Lanz and Hubeny (1995) also rule out a low metallicity, and that their own evaluation of Geneva indices leads to a no ...
... inferred by Paresce (1991) from Geneva photometry, a result that has prompted King and Patten (1992) to suggest that β Pic is a λ Boo star. We note that the HST GHRS data analyzed by Lanz and Hubeny (1995) also rule out a low metallicity, and that their own evaluation of Geneva indices leads to a no ...
Supernovae and compact objects
... November in the evening after sunset, I was contemplating the stars in a clear sky. I noticed that a new and unusual star, surpassing the other stars in brilliancy, was shining almost directly above my head; and since I had, from boyhood, known all the stars of the heavens perfectly, it was quite e ...
... November in the evening after sunset, I was contemplating the stars in a clear sky. I noticed that a new and unusual star, surpassing the other stars in brilliancy, was shining almost directly above my head; and since I had, from boyhood, known all the stars of the heavens perfectly, it was quite e ...
Major Themes of “ The First Stars ”
... and/or metal enrichment metals, dust, CMB, other factors (?) How did the first and second stars form, and what was their IMF? Stellar Evolution and Nucleosynthesis of the First Stars: Approach: numerical stellar evolution and supernova models (1-D) Key Results: “Pair Instability SNe” and “Hypernovae ...
... and/or metal enrichment metals, dust, CMB, other factors (?) How did the first and second stars form, and what was their IMF? Stellar Evolution and Nucleosynthesis of the First Stars: Approach: numerical stellar evolution and supernova models (1-D) Key Results: “Pair Instability SNe” and “Hypernovae ...
Exploring the Early Universe - Solar Physics and Space Weather
... • Heisenberg uncertainty principle for energy and time: the shorter the time interval, the greater the energy uncertainty, or the greater the mass uncertainty • In “empty space”, pairs of particles and antiparticles can spontaneously appear and then disappear anywhere in space provided that each exi ...
... • Heisenberg uncertainty principle for energy and time: the shorter the time interval, the greater the energy uncertainty, or the greater the mass uncertainty • In “empty space”, pairs of particles and antiparticles can spontaneously appear and then disappear anywhere in space provided that each exi ...
acta 20 - Pontifical Academy of Sciences
... What are the key prerequisites for a universe that can offer the arena for this chain of events? Crucial to the whole emergent process is gravity – which enhances density contrasts, and allows structures to form. It is a very weak force. But, unlike the electrical force, everything has the same ‘sig ...
... What are the key prerequisites for a universe that can offer the arena for this chain of events? Crucial to the whole emergent process is gravity – which enhances density contrasts, and allows structures to form. It is a very weak force. But, unlike the electrical force, everything has the same ‘sig ...
01-Introduction
... as a great spiral swarm of discrete particles. Each particle was in elliptic motion about the central nucleus. James Jeans (1916) and Harold Jeffreys proposed a new Tidal Hypothesis in 1917 while World War I was in progress. A passing or grazing star is supposed to have pulled out a long cigar-shape ...
... as a great spiral swarm of discrete particles. Each particle was in elliptic motion about the central nucleus. James Jeans (1916) and Harold Jeffreys proposed a new Tidal Hypothesis in 1917 while World War I was in progress. A passing or grazing star is supposed to have pulled out a long cigar-shape ...
Stars with T eff
... “Investigations of the impact of RGB mass loss upon the HB morphology have mostly relied on the Reimers’s (1975) formula, and it is widely used as a LAW” (Catelan 2005) ...
... “Investigations of the impact of RGB mass loss upon the HB morphology have mostly relied on the Reimers’s (1975) formula, and it is widely used as a LAW” (Catelan 2005) ...
AST 101 INTRODUCTION TO ASTRONOMY SPRING 2008
... formed at the same time; the particle pair would then annihilate each other. D. For every particle created there was also an antiparticle created of the same mass. E. As the temperature of the Universe dropped, the particle creation rate slowed. D 31. ...
... formed at the same time; the particle pair would then annihilate each other. D. For every particle created there was also an antiparticle created of the same mass. E. As the temperature of the Universe dropped, the particle creation rate slowed. D 31. ...
Version0 Answers
... A. As the temperature of the Universe dropped, the particle creation rate slowed. B. Matter and energy are related, according to Einstein’s E = mc2 . C. For every particle created there was also an antiparticle created of the same mass. D. For unknown reasons, there happened to be slightly more matt ...
... A. As the temperature of the Universe dropped, the particle creation rate slowed. B. Matter and energy are related, according to Einstein’s E = mc2 . C. For every particle created there was also an antiparticle created of the same mass. D. For unknown reasons, there happened to be slightly more matt ...
KS4 Earth and Beyond 2637KB
... object and contains about 98% of the total mass in the Solar System. The Sun is a massive ball of hot, glowing gas and is mostly made of hydrogen and helium. It is more than 4.5 billion years old! Scientists once thought that the Sun was powered by chemical reactions but this couldn’t explain how it ...
... object and contains about 98% of the total mass in the Solar System. The Sun is a massive ball of hot, glowing gas and is mostly made of hydrogen and helium. It is more than 4.5 billion years old! Scientists once thought that the Sun was powered by chemical reactions but this couldn’t explain how it ...
Earth and Beyond - Prairie Rose School Division No. 8
... object and contains about 98% of the total mass in the Solar System. The Sun is a massive ball of hot, glowing gas and is mostly made of hydrogen and helium. It is more than 4.5 billion years old! Scientists once thought that the Sun was powered by chemical reactions but this couldn’t explain how it ...
... object and contains about 98% of the total mass in the Solar System. The Sun is a massive ball of hot, glowing gas and is mostly made of hydrogen and helium. It is more than 4.5 billion years old! Scientists once thought that the Sun was powered by chemical reactions but this couldn’t explain how it ...
The Milky Way II AST 112
... • They will explode, supplying enriched material and gas to the ISM. • This material expands, cools, and collapses back into stars… • … and on and on and on. ...
... • They will explode, supplying enriched material and gas to the ISM. • This material expands, cools, and collapses back into stars… • … and on and on and on. ...
Document
... Hubble and expansion • Cepheid variables proved that some galaxies were far way (recognized by variability and VERY luminous). • By 1929, the expansion of the Universe was known, clearly separating galaxies from Galactic nebulae. • Note: it was known that Galactic nebulae had emisson spectra and ga ...
... Hubble and expansion • Cepheid variables proved that some galaxies were far way (recognized by variability and VERY luminous). • By 1929, the expansion of the Universe was known, clearly separating galaxies from Galactic nebulae. • Note: it was known that Galactic nebulae had emisson spectra and ga ...
Modified Newtonian Mechanics
... of stars that have died or have released non-luminous matter into the universe. There are have been no where near the number of these signs seen to accept this hypothesis. There has not been a single black hole detection as the field has looked for to validate the hidden mass hypothesis. This theory ...
... of stars that have died or have released non-luminous matter into the universe. There are have been no where near the number of these signs seen to accept this hypothesis. There has not been a single black hole detection as the field has looked for to validate the hidden mass hypothesis. This theory ...
Lecture 24: High Mass Star Formation Astro 6890/8980 Prof. Tom
... phase. Can undergo Deuterium fusion (for low mass stars) and Hydrogen fusion (high mass stars). Accretion onto star with a disk. Must overcome magnetic pressure, resulting in magnetospheric accretion for low mass stars. Must overcome photon pressure for high mass stars. ...
... phase. Can undergo Deuterium fusion (for low mass stars) and Hydrogen fusion (high mass stars). Accretion onto star with a disk. Must overcome magnetic pressure, resulting in magnetospheric accretion for low mass stars. Must overcome photon pressure for high mass stars. ...
supplemental materials.
... main sequence and red giant models. With no energy source at their centers, no conversion of one element to another and subsequent changes in their stellar structure, and with the bulk of their energy transport via conduction, white dwarfs maintain a nearly constant radius and their evolution is gov ...
... main sequence and red giant models. With no energy source at their centers, no conversion of one element to another and subsequent changes in their stellar structure, and with the bulk of their energy transport via conduction, white dwarfs maintain a nearly constant radius and their evolution is gov ...
Evolved massive stars in W33 and in GMC G23.3-0.3
... and at the parallactic distance of 2.4 kpc (Immer et al. 2013). We spectroscopically detected a few evolved O-type stars and one Wolf-Rayet star, but none of the late-type objects has the luminosity of a RSG star. Several dense molecular cores that may harbor proto clusters were recently discovered ...
... and at the parallactic distance of 2.4 kpc (Immer et al. 2013). We spectroscopically detected a few evolved O-type stars and one Wolf-Rayet star, but none of the late-type objects has the luminosity of a RSG star. Several dense molecular cores that may harbor proto clusters were recently discovered ...
Physics, Chapter 44: Stable Nuclei
... esses. Here the molecular weight of large organic molecules is an important factor in the suitability of a fuel for a particular use, and this may be determined most easily with a mass spectrometer. ...
... esses. Here the molecular weight of large organic molecules is an important factor in the suitability of a fuel for a particular use, and this may be determined most easily with a mass spectrometer. ...
Supernovae
... • At time t=0, mass m 0 of gas is ejected with velocity v0 and total energy E 0. • This interacts with surrounding interstellar material with density r0 and low temperature. ...
... • At time t=0, mass m 0 of gas is ejected with velocity v0 and total energy E 0. • This interacts with surrounding interstellar material with density r0 and low temperature. ...
Document
... – Optically dark objects (that is, only one star is seen in the spectrum, and it is the mass-losing one). – Masses too large to be a white dwarf or a neutron star. ...
... – Optically dark objects (that is, only one star is seen in the spectrum, and it is the mass-losing one). – Masses too large to be a white dwarf or a neutron star. ...
Spectral-Type Trends: Absorption
... stellar luminosity or surface temperature. So, an X-ray emission trend would be very surprising. But stellar winds are stronger and denser for hotter and more luminous stars, so an X-ray hardness trend governed by wind attenuation is expected.) To explore the effect of wind absorption, we have devel ...
... stellar luminosity or surface temperature. So, an X-ray emission trend would be very surprising. But stellar winds are stronger and denser for hotter and more luminous stars, so an X-ray hardness trend governed by wind attenuation is expected.) To explore the effect of wind absorption, we have devel ...
Proudian Senior Seminar - University of Redlands
... e. We cannot tell their age from this figure. ...
... e. We cannot tell their age from this figure. ...
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.