The role of neutron star mergers in the chemical evolution of the
... Observations of heavy element abundances in Galactic halo stars provide important constraints on the astrophysical site(s) of r-process nucleosynthesis. Interestingly, a wide spread is found in the [Eu/Fe] ratios in halo stars (as well as for several s-process elements, such as Ba, Y, La), and is mu ...
... Observations of heavy element abundances in Galactic halo stars provide important constraints on the astrophysical site(s) of r-process nucleosynthesis. Interestingly, a wide spread is found in the [Eu/Fe] ratios in halo stars (as well as for several s-process elements, such as Ba, Y, La), and is mu ...
The Milky Way
... Some neutron stars have magnetic fields ~ 1000 times stronger even than normal neutron stars. These care called Magnetars. ...
... Some neutron stars have magnetic fields ~ 1000 times stronger even than normal neutron stars. These care called Magnetars. ...
The Chemical Composition of Exoplanet
... appropriate quality for this analysis) already exist for many known planetary systems. Therefore, this method provides a simple and widely-applicable first look at the overall composition of an exoplanetary system. This method has been used to study the composition of many exoplanet host stars, howe ...
... appropriate quality for this analysis) already exist for many known planetary systems. Therefore, this method provides a simple and widely-applicable first look at the overall composition of an exoplanetary system. This method has been used to study the composition of many exoplanet host stars, howe ...
Molecular Cooling Rates (Neufeld, Lepp and Melnick 1995)
... produce silicate dusts: prominent 9.7 micron emission features Toward the end of the AGB phase, these stars may become carbon-rich and produce carbonaceous dust ...
... produce silicate dusts: prominent 9.7 micron emission features Toward the end of the AGB phase, these stars may become carbon-rich and produce carbonaceous dust ...
M. Meixner
... resolving power to analyze the mass-loss return from stars to galaxies in the Local Volume of galaxies. For example, color magnitude diagrams from photometric imaging with NIRCam and MIRI can be used to identify dusty evolved stars which can then be compared to precomputed models such as GRAMS to de ...
... resolving power to analyze the mass-loss return from stars to galaxies in the Local Volume of galaxies. For example, color magnitude diagrams from photometric imaging with NIRCam and MIRI can be used to identify dusty evolved stars which can then be compared to precomputed models such as GRAMS to de ...
Slide 1
... After 1H fuses into 4He, the 4He fuses into 12C, 16O, 20Ne, 24Mg, 28Si, … , up to 56Fe Because no H is present, fusion does not form atoms with odd atomic numbers Once 56Fe is formed at the core, fusion stops, the star cools, and collapses in seconds The heat explodes the star into a SUPERNOVA, disp ...
... After 1H fuses into 4He, the 4He fuses into 12C, 16O, 20Ne, 24Mg, 28Si, … , up to 56Fe Because no H is present, fusion does not form atoms with odd atomic numbers Once 56Fe is formed at the core, fusion stops, the star cools, and collapses in seconds The heat explodes the star into a SUPERNOVA, disp ...
Spectra of Cosmic Ray Protons and Helium Produced in Supernova
... interstellar gas, and ma is the mean interstellar atom mass. The escape length is determined from the relative abundance of secondary nuclei (primarily from the Boron-to-Carbon ratio) in cosmic rays. The approximation formula Xe = 19β 3 g/cm2 at R ≤ 3 GV and Xe = 19β 3 (R/3GV)−0.6 g/cm2 at R > 3 GV ...
... interstellar gas, and ma is the mean interstellar atom mass. The escape length is determined from the relative abundance of secondary nuclei (primarily from the Boron-to-Carbon ratio) in cosmic rays. The approximation formula Xe = 19β 3 g/cm2 at R ≤ 3 GV and Xe = 19β 3 (R/3GV)−0.6 g/cm2 at R > 3 GV ...
The Milky Way Galaxy - Academic Computer Center
... Jupiter’s orbit but with a This is called a supermassive mass several million times black hole. Most other galaxies the mass of the Sun. are also thought to have these huge • Since so little light is visible black holes in their centers. from this object it is thought to be a very large black hole. ...
... Jupiter’s orbit but with a This is called a supermassive mass several million times black hole. Most other galaxies the mass of the Sun. are also thought to have these huge • Since so little light is visible black holes in their centers. from this object it is thought to be a very large black hole. ...
Argon is a chemical element represented by the symbol Ar.
... Argon is the third most common gas in the Earth's atmosphere, at 0.93%, making it more common than carbon dioxide. Nearly all of this argon is radiogenic argon-40 derived from the decay of potassium-40 in the Earth's crust. In the universe, argon-36 is by far the most common argon isotope, being the ...
... Argon is the third most common gas in the Earth's atmosphere, at 0.93%, making it more common than carbon dioxide. Nearly all of this argon is radiogenic argon-40 derived from the decay of potassium-40 in the Earth's crust. In the universe, argon-36 is by far the most common argon isotope, being the ...
Stellar Spectra Classification
... Introduction: Classifying stars based on brightness is somewhat problematic. A star’s apparent brightness can be affected by its distance from the observer, its size, or by the presence of interstellar dust. Instead, astronomers classify stars based on the major components of their spectra. Much lik ...
... Introduction: Classifying stars based on brightness is somewhat problematic. A star’s apparent brightness can be affected by its distance from the observer, its size, or by the presence of interstellar dust. Instead, astronomers classify stars based on the major components of their spectra. Much lik ...
The Universe - Mrs. Bills Brainy Bunch
... hypothetical form of energy called dark energy. Some scientists think that dark energy makes up as much as 72% of the total energy content of the universe. ...
... hypothetical form of energy called dark energy. Some scientists think that dark energy makes up as much as 72% of the total energy content of the universe. ...
Summary of recent research activities
... The luminosity-metallicity relation of dIrr galaxies The very low oxygen content of SagDIG, despite a continuous SFH, could be due to galactic winds removing metals from the main body of the galaxy; indeed, for its oxygen abundance, a close-box model would predict a higher gas mass fraction than is ...
... The luminosity-metallicity relation of dIrr galaxies The very low oxygen content of SagDIG, despite a continuous SFH, could be due to galactic winds removing metals from the main body of the galaxy; indeed, for its oxygen abundance, a close-box model would predict a higher gas mass fraction than is ...
3 - Department of Physics and Astronomy : University of Rochester
... An explanation for the origin of life has to be consistent with how much time life had, to become the way it looks now. Until about a century ago, estimating the age of the Universe lay in the domain of religion or philosophy. • Bishop Ussher, “calculating” from the Bible, got the night before 23 ...
... An explanation for the origin of life has to be consistent with how much time life had, to become the way it looks now. Until about a century ago, estimating the age of the Universe lay in the domain of religion or philosophy. • Bishop Ussher, “calculating” from the Bible, got the night before 23 ...
Looking back in time to the big bang theory
... Element can be used as part of teaching this topic or as a consolidation. Learners should be introduced to at least one alternative theory to the Big Bang and reasons why the evidence supports the Big Bang rather than these other theories. Common difficulties and misconceptions include learners thin ...
... Element can be used as part of teaching this topic or as a consolidation. Learners should be introduced to at least one alternative theory to the Big Bang and reasons why the evidence supports the Big Bang rather than these other theories. Common difficulties and misconceptions include learners thin ...
Lecture 21-Hot Big Bang
... the cosmic background radiation changed to microwave Wavelength and its temperature dropped to about 3K. ...
... the cosmic background radiation changed to microwave Wavelength and its temperature dropped to about 3K. ...
The synthesis of organic and inorganic compounds in evolved stars
... ork on stellar nucleosynthesis in the 1950s has led to our current realization that most of the chemical elements are synthesized in stars. Helium is made by hydrogen burning in the core during the main sequence and in a shell above the core in the red giant phase. The element carbon is created by h ...
... ork on stellar nucleosynthesis in the 1950s has led to our current realization that most of the chemical elements are synthesized in stars. Helium is made by hydrogen burning in the core during the main sequence and in a shell above the core in the red giant phase. The element carbon is created by h ...
Connecting Stars, Galaxies and the Universe
... [Fe/H]=-1.5, the 0.8 M⊙ star takes 12 Gyr to reach then end of the main sequence, while its solar metallicity cousin takes about 20 Gyr to do so. Thus, at 0.8 M⊙, Age/[Fe/H] ~ 8 / (-1.5) = -5.3 Gyr/dex. Current random metallicity errors are ~0.03 dex (Terndrup 2009), which correspond to an age unc ...
... [Fe/H]=-1.5, the 0.8 M⊙ star takes 12 Gyr to reach then end of the main sequence, while its solar metallicity cousin takes about 20 Gyr to do so. Thus, at 0.8 M⊙, Age/[Fe/H] ~ 8 / (-1.5) = -5.3 Gyr/dex. Current random metallicity errors are ~0.03 dex (Terndrup 2009), which correspond to an age unc ...
The Most Massive LMC Star Sk
... and bluest of the three components, The members of the cluster probably R 136 a, might be a star of mass formed together. The fainter components (c-f) are probably early-type 0 250-1,000 MG' Cassinelli et al. (1981) stars, as the formation of low mass stars from the IUE data concluded that R 136 a i ...
... and bluest of the three components, The members of the cluster probably R 136 a, might be a star of mass formed together. The fainter components (c-f) are probably early-type 0 250-1,000 MG' Cassinelli et al. (1981) stars, as the formation of low mass stars from the IUE data concluded that R 136 a i ...
Where Do Baby Stars Come From?
... collapse, they get smaller and they rotate faster. Other neat things are also going on. This giant cloud has all sorts of gravitational potential energy in it. The atoms are spread out across space, but there’s a central point to the space. As things move inwards toward that central point, gravitati ...
... collapse, they get smaller and they rotate faster. Other neat things are also going on. This giant cloud has all sorts of gravitational potential energy in it. The atoms are spread out across space, but there’s a central point to the space. As things move inwards toward that central point, gravitati ...
18.9 NOTES What are constellations? Objective: Explain what
... Different constellations and star groups appear over head at different times of the year. The ones visible in the Northern Hemisphere are different from those visible in the Southern Hemisphere. Though stars are relatively stationary, it is the movements of the Earth that make it look as if the star ...
... Different constellations and star groups appear over head at different times of the year. The ones visible in the Northern Hemisphere are different from those visible in the Southern Hemisphere. Though stars are relatively stationary, it is the movements of the Earth that make it look as if the star ...
Chapter15 (with interactive links)
... We observe younger stars to have more heavy elements than older stars. Residing in the disk of our galaxy, the Sun has about a 2% concentration of heavy elements, a relatively high amount. Even globular cluster stars have a small amount of heavy elements, but much less than disk stars. => Ther ...
... We observe younger stars to have more heavy elements than older stars. Residing in the disk of our galaxy, the Sun has about a 2% concentration of heavy elements, a relatively high amount. Even globular cluster stars have a small amount of heavy elements, but much less than disk stars. => Ther ...
Stellar Temperatures
... Stellar Spectral Energy Distributions Stellar temperatures range from ~3000 K to ~100,000 K (although there are exceptions). To zeroth order, they can be considered blackbodies, with stellar absorption lines on top. There is a great variety of stellar absorption lines; the strength of any individua ...
... Stellar Spectral Energy Distributions Stellar temperatures range from ~3000 K to ~100,000 K (although there are exceptions). To zeroth order, they can be considered blackbodies, with stellar absorption lines on top. There is a great variety of stellar absorption lines; the strength of any individua ...
20. Meteorites and the chemical evolution of the Milky Way
... large spherical diffuse stellar halo. Just how these components formed is not known, but there are several competing models (Matteucci, 2003). Most likely, both primordial collapse of a protogalactic gas cloud and subsequent accretion and merger of smaller systems have played a role (Gibson et al., ...
... large spherical diffuse stellar halo. Just how these components formed is not known, but there are several competing models (Matteucci, 2003). Most likely, both primordial collapse of a protogalactic gas cloud and subsequent accretion and merger of smaller systems have played a role (Gibson et al., ...
M - ASTRONOMY GROUP – University of St Andrews
... 1929: Hubble discovers the expansion of the local universe 1929: Einstein’s General Relativity 1948: Gamov predicts background radiation from Big Bang ...
... 1929: Hubble discovers the expansion of the local universe 1929: Einstein’s General Relativity 1948: Gamov predicts background radiation from Big Bang ...
Parameters of massive stars in the Milky Way and nearby galaxies
... atmospheres that include sphericity, mass-loss and line-blanketing, in addition to NLTE. The combination of all these factors results in temperatures that are much cooler than those hitherto assumed. Vacca et al. (1996) presented a compilation of the spectroscopic determinations of effective temper ...
... atmospheres that include sphericity, mass-loss and line-blanketing, in addition to NLTE. The combination of all these factors results in temperatures that are much cooler than those hitherto assumed. Vacca et al. (1996) presented a compilation of the spectroscopic determinations of effective temper ...
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.