Chapter 2 Simulation Methodology 2.1 The generation of cosmological initial conditions
... where the Dg ’s are the linear grown factor for perturbations, which is defined in Peebles [126] and many other places. A closed-form fitting function (much more appropriate for computation) is given in Eisenstein & Hu [194]. δH is a constant describing the amplitude of density fluctuation, which ca ...
... where the Dg ’s are the linear grown factor for perturbations, which is defined in Peebles [126] and many other places. A closed-form fitting function (much more appropriate for computation) is given in Eisenstein & Hu [194]. δH is a constant describing the amplitude of density fluctuation, which ca ...
Star-Galaxy Classification in Multi
... sources with g − r < 1 (left) and g − r > 1 (right). Only stars and galaxies were included in this figure. Only a few percent of the COSMOS point sources are AGNs. Colored curves indicate the upper limit in intrinsic FWHM allowed in the sample. Even in an optimistic scenario where galaxies with FWHM ...
... sources with g − r < 1 (left) and g − r > 1 (right). Only stars and galaxies were included in this figure. Only a few percent of the COSMOS point sources are AGNs. Colored curves indicate the upper limit in intrinsic FWHM allowed in the sample. Even in an optimistic scenario where galaxies with FWHM ...
General relativistic spectra of accretion discs around rapidly
... result, the plotted spectra for these two cases lie almost on top of each other. However, for i ¼ 08 the flux corresponding to the massshed configuration is slightly higher than that for V ¼ 0, while the case is opposite at higher inclinations. This is a result of the inclination dependence of the ð ...
... result, the plotted spectra for these two cases lie almost on top of each other. However, for i ¼ 08 the flux corresponding to the massshed configuration is slightly higher than that for V ¼ 0, while the case is opposite at higher inclinations. This is a result of the inclination dependence of the ð ...
Metallicities of Planet Hosting Stars: A Sample of Giants and Subgiants
... A physical property of planetary systems that has yet to be fully understood is a connection between planetary formation and the metallicities of the host stars. There is now unequivocal evidence that main sequence (MS) FGK-type dwarfs known to have at least one giant planet (i.e., Mp ≥ 1 MJ , where ...
... A physical property of planetary systems that has yet to be fully understood is a connection between planetary formation and the metallicities of the host stars. There is now unequivocal evidence that main sequence (MS) FGK-type dwarfs known to have at least one giant planet (i.e., Mp ≥ 1 MJ , where ...
Photometric transit search for planets around cool stars from the
... their radii which can in turn provide a useful testing ground for improving stellar evolution models. Secondly, degeneracies in the models of the physical structures of Super-Earths, such as objects with very different compositions having similar masses and radii, also prevent one from exactly infer ...
... their radii which can in turn provide a useful testing ground for improving stellar evolution models. Secondly, degeneracies in the models of the physical structures of Super-Earths, such as objects with very different compositions having similar masses and radii, also prevent one from exactly infer ...
An asymmetry detected in the disk of κ CMa⋆ with the AMBER/VLTI
... Harmanec (1988) compilation for the effective temperatures given by Popper (1980), Prinja (1989) and Fremat (2005). ...
... Harmanec (1988) compilation for the effective temperatures given by Popper (1980), Prinja (1989) and Fremat (2005). ...
Modelling the Ultra-Faint Dwarf Galaxies and Tidal
... – At the Orphan Stream: if the progenitor was more massive than 106 Msolar than we should see the wrap around of the leading arm at the same position but at different distances & velocities – At UMa II: if the satellite is DM dominated the contours should become smoother; if UMa II is the progenitor ...
... – At the Orphan Stream: if the progenitor was more massive than 106 Msolar than we should see the wrap around of the leading arm at the same position but at different distances & velocities – At UMa II: if the satellite is DM dominated the contours should become smoother; if UMa II is the progenitor ...
Lecture 16, AGN Evolution
... – Optical spectra similar to those of quasars, yet radio emission weak or absent – Now called QSOs (“quasi-stellar objects”), but common to use terms interchangeably – About 10x more numerous than radio-loud quasars ...
... – Optical spectra similar to those of quasars, yet radio emission weak or absent – Now called QSOs (“quasi-stellar objects”), but common to use terms interchangeably – About 10x more numerous than radio-loud quasars ...
Surface temperature distribution and absorption features in Isolated
... the equation of state (EoS) P = P (ρ), if the medium is barotrope. It is determined by the model adopted to describe the matter inside the star. This system of differential equations is solved imposing the boundary conditions ρ(0) = ρc and P (R? ) = 0. Once the NS radius R? is fixed, the solution pr ...
... the equation of state (EoS) P = P (ρ), if the medium is barotrope. It is determined by the model adopted to describe the matter inside the star. This system of differential equations is solved imposing the boundary conditions ρ(0) = ρc and P (R? ) = 0. Once the NS radius R? is fixed, the solution pr ...
lecture24
... Spiral galaxies have a basic disk shape with the spiral arms in the flat disk. There is a central core containing the bulk of the stars, visible here as bright hubs (99% of the light) from which the spirals radiate. And like the Milky Way, there is a sparsely populated halo of stars. Spirals come wi ...
... Spiral galaxies have a basic disk shape with the spiral arms in the flat disk. There is a central core containing the bulk of the stars, visible here as bright hubs (99% of the light) from which the spirals radiate. And like the Milky Way, there is a sparsely populated halo of stars. Spirals come wi ...
Matter Cycle in the Interstellar Medium (ISM)
... Dark nebulae: originally thought to be holes in the star clouds ; later recognized to be dark clouds of obscuring material seen in silhouette against rich star fields. Especially prominent in the brightest regions of the Milky Way (e.g., the Great Rift in Cygnus or the Coal Sack in the Southern Mi ...
... Dark nebulae: originally thought to be holes in the star clouds ; later recognized to be dark clouds of obscuring material seen in silhouette against rich star fields. Especially prominent in the brightest regions of the Milky Way (e.g., the Great Rift in Cygnus or the Coal Sack in the Southern Mi ...
Day of Planetaria 2016: March 12th at Astronomical Centre Rijeka
... The Little Star that Could (planetarium show for the children) The Little Star That Could is a story about an average yellow star on a search for planets of his own to warm and protect. Along his way, he encounters other stars, learns what makes each star special, and discovers that stars can combi ...
... The Little Star that Could (planetarium show for the children) The Little Star That Could is a story about an average yellow star on a search for planets of his own to warm and protect. Along his way, he encounters other stars, learns what makes each star special, and discovers that stars can combi ...
REVIEWS 18 years of science with the Hubble Space Telescope Julianne J. Dalcanton
... their masses, and, because the stars in the binary can be assumed to have formed simultaneously, it can also be assumed that they have a common age and metallicity. Binaries are thus particularly useful when studying poorly understood types of star. Unfortunately, most stars are far enough away that ...
... their masses, and, because the stars in the binary can be assumed to have formed simultaneously, it can also be assumed that they have a common age and metallicity. Binaries are thus particularly useful when studying poorly understood types of star. Unfortunately, most stars are far enough away that ...
Galaxy Collisions, Gas Stripping and Star Formation in the Evolution
... An overabundance of spiral galaxies and an under abundance of S0 galaxies in highredshift clusters, when it is compared to low z clusters, is a consequences of galaxy merger events and of other environmental effects. In ΛDCM cosmological models with Ω0 = 0.4 and ΩΛ = 0.6, the galaxy interactions and ...
... An overabundance of spiral galaxies and an under abundance of S0 galaxies in highredshift clusters, when it is compared to low z clusters, is a consequences of galaxy merger events and of other environmental effects. In ΛDCM cosmological models with Ω0 = 0.4 and ΩΛ = 0.6, the galaxy interactions and ...
An evolutionary channel towards the accreting millisecond pulsar
... vicinity of the pulsar is assumed to carry away the specific orbital angular momentum of the pulsar (Tauris & Savonije 1999), while the donor-star winds were assumed to be ejected from the inner Lagrangian point by the radiation pressure of the pulsar (Burderi & Possenti 2001), and carry away the sp ...
... vicinity of the pulsar is assumed to carry away the specific orbital angular momentum of the pulsar (Tauris & Savonije 1999), while the donor-star winds were assumed to be ejected from the inner Lagrangian point by the radiation pressure of the pulsar (Burderi & Possenti 2001), and carry away the sp ...
Numerical Star-Formation Studies-
... the hydrogen-burning centers of the final stars is enormous, about 24 orders of magnitude, and so is the corresponding spatial range (roughly 8 orders of magnitude). In addition to the large dynamical range, many different physical processes play a role at the various stages of the contraction proce ...
... the hydrogen-burning centers of the final stars is enormous, about 24 orders of magnitude, and so is the corresponding spatial range (roughly 8 orders of magnitude). In addition to the large dynamical range, many different physical processes play a role at the various stages of the contraction proce ...
The role of tidal interactions in star formation
... the angular momentum of a solar mass of material in an interstellar cloud rotating with the Galaxy, and showed that this is many orders of magnitude more than can be accommodated in a single star even when rotating at breakup speed (Mestel 1965; Spitzer 1968). We have learned since then that stars f ...
... the angular momentum of a solar mass of material in an interstellar cloud rotating with the Galaxy, and showed that this is many orders of magnitude more than can be accommodated in a single star even when rotating at breakup speed (Mestel 1965; Spitzer 1968). We have learned since then that stars f ...
Star Formation in Isolated Disk Galaxies. I. Models and
... In the present simulations, we interpret the creation of sink particles as representing the formation of molecular gas and stellar clusters. We neglect recycling of gas from molecular clouds back into the warm atomic and ionized medium represented by SPH particles in our simulation, however, an impo ...
... In the present simulations, we interpret the creation of sink particles as representing the formation of molecular gas and stellar clusters. We neglect recycling of gas from molecular clouds back into the warm atomic and ionized medium represented by SPH particles in our simulation, however, an impo ...
d+p 3He
... “Certain physical investigations in the past year make it probable to my mind that some portion of sub-atomic energy is actually set free in the stars … If only five percent of a star’s mass consists initially of hydrogen atoms which are gradually being combined to form more complex elements, the to ...
... “Certain physical investigations in the past year make it probable to my mind that some portion of sub-atomic energy is actually set free in the stars … If only five percent of a star’s mass consists initially of hydrogen atoms which are gradually being combined to form more complex elements, the to ...
White dwarfmain sequence binaries identified within SDSS DR7 and
... Gómez-Morán & Schwope (2007) also developed special colourcuts to select old WDMS systems from the Sloan Extension for Galactic Understanding and Exploration (SEGUE), but they did not consider the fact that the colours change with different surface gravities of white dwarfs and metallicities of co ...
... Gómez-Morán & Schwope (2007) also developed special colourcuts to select old WDMS systems from the Sloan Extension for Galactic Understanding and Exploration (SEGUE), but they did not consider the fact that the colours change with different surface gravities of white dwarfs and metallicities of co ...
pp-chain
... “Certain physical investigations in the past year make it probable to my mind that some portion of sub-atomic energy is actually set free in the stars … If only five percent of a star’s mass consists initially of hydrogen atoms which are gradually being combined to form more complex elements, the to ...
... “Certain physical investigations in the past year make it probable to my mind that some portion of sub-atomic energy is actually set free in the stars … If only five percent of a star’s mass consists initially of hydrogen atoms which are gradually being combined to form more complex elements, the to ...
masses of star clusters in the nuclei of bulgeless spiral galaxies
... Space Telescope WFPC2 and spherically symmetric dynamical models, we determine masses between 8 ; 105 and 6 ; 107 M . The mass-to-light ratios range from 0.2 to 1.5 in the I band. This indicates a young mean age for most clusters, in agreement with previous studies. Given their high masses and smal ...
... Space Telescope WFPC2 and spherically symmetric dynamical models, we determine masses between 8 ; 105 and 6 ; 107 M . The mass-to-light ratios range from 0.2 to 1.5 in the I band. This indicates a young mean age for most clusters, in agreement with previous studies. Given their high masses and smal ...
The Occurrence Rate of Small Planets Around Small Stars
... more optimistic. For instance, Haberle et al. (1996) and Joshi et al. (1997) demonstrated that sufficient quantities of carbon dioxide could prevent the atmosphere from freezing and Pierrehumbert (2011) reported that a tidally-locked planet could be in a partially habitable “Eyeball Earth” state in ...
... more optimistic. For instance, Haberle et al. (1996) and Joshi et al. (1997) demonstrated that sufficient quantities of carbon dioxide could prevent the atmosphere from freezing and Pierrehumbert (2011) reported that a tidally-locked planet could be in a partially habitable “Eyeball Earth” state in ...
REVIEW Numerical Star-Formation Studies— A Status Report
... Santa Cruz and at Leiden Observatory. He got his Ph.D. in 1998 from Heidelberg University for his work on star cluster formation with Andreas Burkert at the Max Planck Institute for Astronomy. Ralf Klessen received the Ludwig Biermann Prize of the German Astronomical Society and the Otto Hahn Award ...
... Santa Cruz and at Leiden Observatory. He got his Ph.D. in 1998 from Heidelberg University for his work on star cluster formation with Andreas Burkert at the Max Planck Institute for Astronomy. Ralf Klessen received the Ludwig Biermann Prize of the German Astronomical Society and the Otto Hahn Award ...
Document
... “Certain physical investigations in the past year make it probable to my mind that some portion of sub-atomic energy is actually set free in the stars … If only five percent of a star’s mass consists initially of hydrogen atoms which are gradually being combined to form more complex elements, the to ...
... “Certain physical investigations in the past year make it probable to my mind that some portion of sub-atomic energy is actually set free in the stars … If only five percent of a star’s mass consists initially of hydrogen atoms which are gradually being combined to form more complex elements, the to ...
Main sequence
In astronomy, the main sequence is a continuous and distinctive band of stars that appears on plots of stellar color versus brightness. These color-magnitude plots are known as Hertzsprung–Russell diagrams after their co-developers, Ejnar Hertzsprung and Henry Norris Russell. Stars on this band are known as main-sequence stars or ""dwarf"" stars.After a star has formed, it generates thermal energy in the dense core region through the nuclear fusion of hydrogen atoms into helium. During this stage of the star's lifetime, it is located along the main sequence at a position determined primarily by its mass, but also based upon its chemical composition and other factors. All main-sequence stars are in hydrostatic equilibrium, where outward thermal pressure from the hot core is balanced by the inward pressure of gravitational collapse from the overlying layers. The strong dependence of the rate of energy generation in the core on the temperature and pressure helps to sustain this balance. Energy generated at the core makes its way to the surface and is radiated away at the photosphere. The energy is carried by either radiation or convection, with the latter occurring in regions with steeper temperature gradients, higher opacity or both.The main sequence is sometimes divided into upper and lower parts, based on the dominant process that a star uses to generate energy. Stars below about 1.5 times the mass of the Sun (or 1.5 solar masses (M☉)) primarily fuse hydrogen atoms together in a series of stages to form helium, a sequence called the proton–proton chain. Above this mass, in the upper main sequence, the nuclear fusion process mainly uses atoms of carbon, nitrogen and oxygen as intermediaries in the CNO cycle that produces helium from hydrogen atoms. Main-sequence stars with more than two solar masses undergo convection in their core regions, which acts to stir up the newly created helium and maintain the proportion of fuel needed for fusion to occur. Below this mass, stars have cores that are entirely radiative with convective zones near the surface. With decreasing stellar mass, the proportion of the star forming a convective envelope steadily increases, whereas main-sequence stars below 0.4 M☉ undergo convection throughout their mass. When core convection does not occur, a helium-rich core develops surrounded by an outer layer of hydrogen.In general, the more massive a star is, the shorter its lifespan on the main sequence. After the hydrogen fuel at the core has been consumed, the star evolves away from the main sequence on the HR diagram. The behavior of a star now depends on its mass, with stars below 0.23 M☉ becoming white dwarfs directly, whereas stars with up to ten solar masses pass through a red giant stage. More massive stars can explode as a supernova, or collapse directly into a black hole.