Survey of the Universe
... phenomenon – galaxies colliding, inferno in the center of an active galaxy (an Active Galactic Nucleus, or “AGN”). Reminder of the GZK cutoff: • If particles accelerated to energies greater than 1019 eV originate at distances greater than about 150 Million Light Years, they will lose energy by inter ...
... phenomenon – galaxies colliding, inferno in the center of an active galaxy (an Active Galactic Nucleus, or “AGN”). Reminder of the GZK cutoff: • If particles accelerated to energies greater than 1019 eV originate at distances greater than about 150 Million Light Years, they will lose energy by inter ...
The Milky Way at Different Wavelengths
... In the Milky Way, extended soft X-ray emission is detected from hot, shocked gas. At the lower energies especially, the interstellar medium strongly absorbs X-rays, and cold clouds of interstellar gas are seen as shadows against background X-ray emission. Color variations indicate variations of abso ...
... In the Milky Way, extended soft X-ray emission is detected from hot, shocked gas. At the lower energies especially, the interstellar medium strongly absorbs X-rays, and cold clouds of interstellar gas are seen as shadows against background X-ray emission. Color variations indicate variations of abso ...
CENTRAL MICHIGAN UNIVERSITY
... observational properties, double stars, variable stars, stellar structure, and the stages of stellar evolution. ...
... observational properties, double stars, variable stars, stellar structure, and the stages of stellar evolution. ...
Abundances and possible diffusion of elements in M 67 stars⋆
... the Sun and solar twins in the solar neighbourhood, and to explore selective atomic diffusion of chemical elements as predicted by stellar-structure theory. Methods. We have obtained VLT/FLAMES-UVES spectra and analysed these strictly differentially in order to explore chemicalabundance similarities a ...
... the Sun and solar twins in the solar neighbourhood, and to explore selective atomic diffusion of chemical elements as predicted by stellar-structure theory. Methods. We have obtained VLT/FLAMES-UVES spectra and analysed these strictly differentially in order to explore chemicalabundance similarities a ...
Helium - Boreal Science
... in the universe. Only Hydrogen is more abundant! These two elements were copiously formed during the creation of the universe. In the early stages of the universe, helium and hydrogen nuclei were actually formed. No atoms were formed until about 300,000 years after the Big Bang took place, when the ...
... in the universe. Only Hydrogen is more abundant! These two elements were copiously formed during the creation of the universe. In the early stages of the universe, helium and hydrogen nuclei were actually formed. No atoms were formed until about 300,000 years after the Big Bang took place, when the ...
Isotopic composition of Hg and Pt in 5 slowly rotating HgMn stars *
... 1:67 for the ratio of the radii of the primary to the secondary stars, and Te = 9200 K, log g = 4:2, a microturbulent velocity = 2:0 km s;1 , and v sin i = 2 km s;1 for the secondary. Furthermore, we assumed solar chemical composition for this star, in spite of the fact that Wahlgren at al. (1994 ...
... 1:67 for the ratio of the radii of the primary to the secondary stars, and Te = 9200 K, log g = 4:2, a microturbulent velocity = 2:0 km s;1 , and v sin i = 2 km s;1 for the secondary. Furthermore, we assumed solar chemical composition for this star, in spite of the fact that Wahlgren at al. (1994 ...
observational requirements, feasability, expectations
... Need for a precise correction of very low frequency instrumental noise!! Good to have ground observations to have Ca H & K measurements (Mt Wilson index) ...
... Need for a precise correction of very low frequency instrumental noise!! Good to have ground observations to have Ca H & K measurements (Mt Wilson index) ...
SOLUTIONS TO PROBLEM SET # 3
... 5) [20 points] If every star within a Hubble distance of us were as massive as the Sun and were made entirely of hydrogen, how many hydrogen atoms would be within a Hubble distance of us? Dividing this number of atoms by the volume of space within a Hubble distance of us, show how many hydrogen ato ...
... 5) [20 points] If every star within a Hubble distance of us were as massive as the Sun and were made entirely of hydrogen, how many hydrogen atoms would be within a Hubble distance of us? Dividing this number of atoms by the volume of space within a Hubble distance of us, show how many hydrogen ato ...
Gamma-Ray Line Emission from Radioactive Isotopes in Stars and
... Al abundance present in the hydrogen shell is ejected unmodified in the supernova explosion or, in more massive stars during their Wolf-Rayet phase, by a stellar wind. The 26Al synthesized in the oxygen-neon shell may be significantly enhanced because of operation of the neutrino process (Woosley et ...
... Al abundance present in the hydrogen shell is ejected unmodified in the supernova explosion or, in more massive stars during their Wolf-Rayet phase, by a stellar wind. The 26Al synthesized in the oxygen-neon shell may be significantly enhanced because of operation of the neutrino process (Woosley et ...
Cosmic Times - Klenk Astronomy
... Gravitation was confirmed when the light from stars was bent around the sun • Einstein’s model also predicted that the universe is either expanding or contracting • He didn’t like this so he added a universal (or cosmological ...
... Gravitation was confirmed when the light from stars was bent around the sun • Einstein’s model also predicted that the universe is either expanding or contracting • He didn’t like this so he added a universal (or cosmological ...
Which Stars Form Black Holes and Neutron Stars?
... with M>8 M⊙ have M>25 M⊙ . If half of the massive stars produce black holes and half produce magnetars, it would explain why the birth rates of magnetars are only ∼10% of those of radio pulsars [38, 24, 25]. Second, it implies that some mechanism allows >30 M⊙ stars to lose >95% of their mass and le ...
... with M>8 M⊙ have M>25 M⊙ . If half of the massive stars produce black holes and half produce magnetars, it would explain why the birth rates of magnetars are only ∼10% of those of radio pulsars [38, 24, 25]. Second, it implies that some mechanism allows >30 M⊙ stars to lose >95% of their mass and le ...
Slide 1
... * The homogeneity of the stars in these clusters (note the similar colours of all the stars in the image of NGC104 above) indicates that they have similar chemical compositions and similar ages. This makes them the simplest systems to use to test theoretical models of star formation and evolution. * ...
... * The homogeneity of the stars in these clusters (note the similar colours of all the stars in the image of NGC104 above) indicates that they have similar chemical compositions and similar ages. This makes them the simplest systems to use to test theoretical models of star formation and evolution. * ...
Hot Stars With Cool Companions
... As a final pre-processing step, we removed the rotationally broadened spectral lines of the primary star by fitting a cubic Savitzky-Golay (Savitzky & Golay 1964) smoothing spline with a window size of 0.8v sin i, where the v sin i came from the most recent literature value in the Simbad database. T ...
... As a final pre-processing step, we removed the rotationally broadened spectral lines of the primary star by fitting a cubic Savitzky-Golay (Savitzky & Golay 1964) smoothing spline with a window size of 0.8v sin i, where the v sin i came from the most recent literature value in the Simbad database. T ...
Lecture 39: Early Universe Test 3 overview 11/21
... • Formation of planets. temperature of solar nebula, and how it varies with distance type of planet formed. Heavy elements freeze out first. Extrasolar planets detected in a number of ways (motion of stars, planet eclipsing star, directly). Planetary atmospheres: high temp and/or low surface gravi ...
... • Formation of planets. temperature of solar nebula, and how it varies with distance type of planet formed. Heavy elements freeze out first. Extrasolar planets detected in a number of ways (motion of stars, planet eclipsing star, directly). Planetary atmospheres: high temp and/or low surface gravi ...
Galaxy Formation,! Reionization, ! the First Stars and Quasars! Ay 127!
... • The early stages of galaxy evolution - but there is no clear-cut boundary, and it also has two principal aspects: assembly of the mass, and conversion of gas into stars! • Must be related to large-scale (hierarchical) structure formation, plus the dissipative processes - it is a very messy proce ...
... • The early stages of galaxy evolution - but there is no clear-cut boundary, and it also has two principal aspects: assembly of the mass, and conversion of gas into stars! • Must be related to large-scale (hierarchical) structure formation, plus the dissipative processes - it is a very messy proce ...
History of Star Formation in Local Galaxies
... The Stellar Populations of the SMC Full analysis of the CMDs is not complete yet, but simply from comparing the CMDs to isochrones, we find that the SMC does have 10-12 Gyr old stars. Just not that many. Thus the SMC had a slow start to its formation… which maybe a reason so few globular clusters f ...
... The Stellar Populations of the SMC Full analysis of the CMDs is not complete yet, but simply from comparing the CMDs to isochrones, we find that the SMC does have 10-12 Gyr old stars. Just not that many. Thus the SMC had a slow start to its formation… which maybe a reason so few globular clusters f ...
Chemical Composition of Planetary Nebulae: The Galaxy and the
... degree of accuracy. These correlations can then be compared with the predictions of the nucleosynthetical processes and chemical evolution models of intermediate mass stars (see for example [15], [7], [12]) and act as constraints on these models. In particular, it is known that there is a general me ...
... degree of accuracy. These correlations can then be compared with the predictions of the nucleosynthetical processes and chemical evolution models of intermediate mass stars (see for example [15], [7], [12]) and act as constraints on these models. In particular, it is known that there is a general me ...
The 13C(α,n)16O reaction rate. Recent estimates, new
... osynthesis in low mass stars. The above mentioned reaction is important because it is considered as the dominant neutron source active in stars with a mass included in the range 0.8 - 3 M⊙ , which actively contribute to the nucleosynthesis of heavy nuclei through neutron capture processes. Roughly ...
... osynthesis in low mass stars. The above mentioned reaction is important because it is considered as the dominant neutron source active in stars with a mass included in the range 0.8 - 3 M⊙ , which actively contribute to the nucleosynthesis of heavy nuclei through neutron capture processes. Roughly ...
PHYS 1400 Sample Exam Questions: Properties of Matter (Atoms) 1
... A) Nothing, really. A scientific paper in a peer-reviewed journal and a big-eyed kitten painted on black velvet are both valid ways of describing the universe. Both are just somebody's opinion. B) Science is rigid, but literature is flexible. A scientific paper must follow certain rules (like having ...
... A) Nothing, really. A scientific paper in a peer-reviewed journal and a big-eyed kitten painted on black velvet are both valid ways of describing the universe. Both are just somebody's opinion. B) Science is rigid, but literature is flexible. A scientific paper must follow certain rules (like having ...
(March 2004) (ppt-format) - RHIG
... Chiral symmetry is a exact symmetry only for massless quarks. In a massless world, quarks are either left or right handed The QCD Lagrangian is symmetric with respect to left/right handed quarks. Confinement results in a large dynamical mass - constituent mass. chiral symmetry is broken (o ...
... Chiral symmetry is a exact symmetry only for massless quarks. In a massless world, quarks are either left or right handed The QCD Lagrangian is symmetric with respect to left/right handed quarks. Confinement results in a large dynamical mass - constituent mass. chiral symmetry is broken (o ...
Monday, April 28
... Herschel’s Findings • Stars thinned out very fast at right angles to Milky Way • In the plane of the Milky Way the thinning was slower and depended upon the direction in which he looked • Flaws: – Observations made only in visible spectrum – Did not take into account absorption by interstellar gas ...
... Herschel’s Findings • Stars thinned out very fast at right angles to Milky Way • In the plane of the Milky Way the thinning was slower and depended upon the direction in which he looked • Flaws: – Observations made only in visible spectrum – Did not take into account absorption by interstellar gas ...
The central star of the planetary nebula PB 8: a Wolf-Rayet
... A considerable fraction of the central stars of planetary nebulæ (CSPNe) are hydrogen-deficient. As a rule, these CSPNe exhibit a chemical composition of helium, carbon, and oxygen with the majority showing Wolf-Rayet-like emission line spectra. These stars are classified as CSPNe of a spectral type ...
... A considerable fraction of the central stars of planetary nebulæ (CSPNe) are hydrogen-deficient. As a rule, these CSPNe exhibit a chemical composition of helium, carbon, and oxygen with the majority showing Wolf-Rayet-like emission line spectra. These stars are classified as CSPNe of a spectral type ...
n - Indico
... • A. Best, A. Di Leva, G. Imbriani, | Università di Napoli and INFN Napoli, Italy • G. Gervino | Università di Torino and INFN Torino, Italy • M. Aliotta, C. Bruno, T. Davinson | University of Edinburgh, United Kingdom • G. D’Erasmo, E.M. Fiore, V. Mossa, F. Pantaleo, V. Paticchio, R. Perrino*, L. S ...
... • A. Best, A. Di Leva, G. Imbriani, | Università di Napoli and INFN Napoli, Italy • G. Gervino | Università di Torino and INFN Torino, Italy • M. Aliotta, C. Bruno, T. Davinson | University of Edinburgh, United Kingdom • G. D’Erasmo, E.M. Fiore, V. Mossa, F. Pantaleo, V. Paticchio, R. Perrino*, L. S ...
The Triple-Ring Nebula: Fingerprint of a Binary Merger
... 4 A Binary Merger Model for the Progenitor of SN 1987A The idea that the anomalous properties of the progenitor of SN 1987A are the result of the merger of two stars about 20,000 years before the explosion has long been the leading model for the progenitor8 . In this model, the system consisted init ...
... 4 A Binary Merger Model for the Progenitor of SN 1987A The idea that the anomalous properties of the progenitor of SN 1987A are the result of the merger of two stars about 20,000 years before the explosion has long been the leading model for the progenitor8 . In this model, the system consisted init ...
Document
... Stars with small masses (less than a solar mass) are much more common than massive stars (stars more than about 15 to 20 solar masses). The highest mass stars are very hot and luminous, and can alter the cloud environment. ...
... Stars with small masses (less than a solar mass) are much more common than massive stars (stars more than about 15 to 20 solar masses). The highest mass stars are very hot and luminous, and can alter the cloud environment. ...
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.