$doc.title
... obje t brighter than about 1/3 L , whi h orresponds to a period of about 5 minutes for a 1.4 M neutron star mass donor. Additionally, ultra ompa t binaries should stand out as being too hot for their magnitudes when plotted in a olor magnitude diagram. We note that ar hival HST data an be used ...
... obje t brighter than about 1/3 L , whi h orresponds to a period of about 5 minutes for a 1.4 M neutron star mass donor. Additionally, ultra ompa t binaries should stand out as being too hot for their magnitudes when plotted in a olor magnitude diagram. We note that ar hival HST data an be used ...
A Note on the Mixing Length Theory and Massive Star Evolution
... in the hydrogen ionization zone, where the relative temperature fluctuations are much larger than unity. This is due to the fact that while the density is very low in the atmosphere of giants and supergiants and therefore convection is not efficient, in the hydrogen ionization zone, the opacity is e ...
... in the hydrogen ionization zone, where the relative temperature fluctuations are much larger than unity. This is due to the fact that while the density is very low in the atmosphere of giants and supergiants and therefore convection is not efficient, in the hydrogen ionization zone, the opacity is e ...
Steven R. Majewski - UCLA Physics & Astronomy
... – “central cusps problem” – “angular momentum problems” Abadi et al. (2003): “Current cosmological simulations have difficulties making anything that looks like a real galaxy.” ...
... – “central cusps problem” – “angular momentum problems” Abadi et al. (2003): “Current cosmological simulations have difficulties making anything that looks like a real galaxy.” ...
![arXiv:1007.5481v1 [astro-ph.EP] 30 Jul 2010](http://s1.studyres.com/store/data/016640559_1-8bc20118c4d48efd5cfe1f2b10a85bec-300x300.png)
arXiv:1007.5481v1 [astro-ph.EP] 30 Jul 2010
... the orbital period measured by CoRoT. The solid curve represents the best fit solution. Lower panel: Residuals to the fit. In both panels, the white symbols indicate the measurements that have been corrected for moonlight contamination. ...
... the orbital period measured by CoRoT. The solid curve represents the best fit solution. Lower panel: Residuals to the fit. In both panels, the white symbols indicate the measurements that have been corrected for moonlight contamination. ...
August 2015 BRAS Newsletter
... telescope, a soft, bluish-green glow can be seen to surround the ‘dumbbell’; and was the first planetary nebula discovered – by Charles Messier in 1764. Brocchi’s Cluster, Al Sufi’s Cluster, Collinder 399, The Coathanger (asterism), mag. 3.6, 19 25.4 +20 11, 90’, is a group of stars with magnitudes ...
... telescope, a soft, bluish-green glow can be seen to surround the ‘dumbbell’; and was the first planetary nebula discovered – by Charles Messier in 1764. Brocchi’s Cluster, Al Sufi’s Cluster, Collinder 399, The Coathanger (asterism), mag. 3.6, 19 25.4 +20 11, 90’, is a group of stars with magnitudes ...
stellar diameters and temperatures. iii. main-sequence a, f, g
... we used the SearchCal tool developed by the JMMC Working Group (Bonneau et al. 2006, 2011). These calibrator stars are listed in Table 1 , and the value of the estimated angular diameters θEST is taken from the SearchCal catalog value for the estimated limb-darkened angular diameter. In order to ens ...
... we used the SearchCal tool developed by the JMMC Working Group (Bonneau et al. 2006, 2011). These calibrator stars are listed in Table 1 , and the value of the estimated angular diameters θEST is taken from the SearchCal catalog value for the estimated limb-darkened angular diameter. In order to ens ...
Constraints on the Production of Ultra–High
... of inertia I D 1045 ergs s2, a star such as PSR 1937]21 has a rotational energy E \ 1 Iu2 D 1052 ergs, many orders of magnitude greater than2 the D1046.5 ergs required per neutron star. Thus, even if most neutron stars rotate more slowly and the efficiency of cosmic-ray generation is much less than ...
... of inertia I D 1045 ergs s2, a star such as PSR 1937]21 has a rotational energy E \ 1 Iu2 D 1052 ergs, many orders of magnitude greater than2 the D1046.5 ergs required per neutron star. Thus, even if most neutron stars rotate more slowly and the efficiency of cosmic-ray generation is much less than ...
Non-Thermal Radio Emission from Binary Systems
... 5 GHz with a radio telescope with a typical minimum flux density of 1 mJy: the quiet Sun: the slowly varying component: the very strong solar radio bursts: ...
... 5 GHz with a radio telescope with a typical minimum flux density of 1 mJy: the quiet Sun: the slowly varying component: the very strong solar radio bursts: ...
http://www.lanl.gov/orgs/adtsc/publications/science_highlights_2013/docs/Pg24_25.pdf
... combinations of progenitor properties. To perform a more controlled test of the accuracy of our code, we are beginning a project to match a simulation to SN 1987A. We chose this SN as a test case since it has been very consistently and thoroughly observed since it first exploded, due to its nearby l ...
... combinations of progenitor properties. To perform a more controlled test of the accuracy of our code, we are beginning a project to match a simulation to SN 1987A. We chose this SN as a test case since it has been very consistently and thoroughly observed since it first exploded, due to its nearby l ...
Presentation - Copernicus.org
... Arizona), Dmitry Savransky (Princeton Univ. and Lawrence Livermore National Laboratory) ...
... Arizona), Dmitry Savransky (Princeton Univ. and Lawrence Livermore National Laboratory) ...
neutron star - Chabot College
... • A white dwarf supernova arises from the explosion of an entire white dwarf triggered by carbon fusion when it gains enough mass to approach the 1.4 Msunlimit. The peak luminosity of the explosion exceeds 10 billion times the Sun’s. Because these supernovae have nearly identical light curves, and b ...
... • A white dwarf supernova arises from the explosion of an entire white dwarf triggered by carbon fusion when it gains enough mass to approach the 1.4 Msunlimit. The peak luminosity of the explosion exceeds 10 billion times the Sun’s. Because these supernovae have nearly identical light curves, and b ...
Roche accretion of stars close to massive black holes
... In this paper, we consider Roche accretion in an extreme mass-ratio inspiral binary system formed by a star orbiting a massive black hole. The ultimate goal is to constrain the mass and spin of the black hole and provide a test of general relativity in the strong-field regime from the resultant quas ...
... In this paper, we consider Roche accretion in an extreme mass-ratio inspiral binary system formed by a star orbiting a massive black hole. The ultimate goal is to constrain the mass and spin of the black hole and provide a test of general relativity in the strong-field regime from the resultant quas ...
SouthamptonTalkPitkin - LIGO dcc
... For two 1.4 M⊙ neutron stars near coalescence at a distance of 10 Mpc ℎ~1.4 × 10−22 ...
... For two 1.4 M⊙ neutron stars near coalescence at a distance of 10 Mpc ℎ~1.4 × 10−22 ...
How Stars Work (Part II)
... Energy transport (1/2) Three mechanisms for energy transport 1. Conduction: heat flows from hot to cold Energy transferred from atom to atom E.g. handle of frying pan on stove 2. Radiative diffusion: high energy photons interact with matter give up some of their energy, replenishing local heat supp ...
... Energy transport (1/2) Three mechanisms for energy transport 1. Conduction: heat flows from hot to cold Energy transferred from atom to atom E.g. handle of frying pan on stove 2. Radiative diffusion: high energy photons interact with matter give up some of their energy, replenishing local heat supp ...
an approach to effective temperature and surface gravity in post
... SDSS gri photometric systems for main sequence stars. These transformations provide absolute magnitude and distance determinations which can be used in space density evaluations at short distances where some or all of the gri magnitudes are saturated. These authors also showed that those formulae we ...
... SDSS gri photometric systems for main sequence stars. These transformations provide absolute magnitude and distance determinations which can be used in space density evaluations at short distances where some or all of the gri magnitudes are saturated. These authors also showed that those formulae we ...
Overview spherical accretion
... if a region expands, the velocity dispersion will decrease A simple example of an incompressible flow in phase space is provided by an idealized marathon race in which all runners travel at constant speed. At the start of the course, the density of runners is large, but they travel at a wide variety ...
... if a region expands, the velocity dispersion will decrease A simple example of an incompressible flow in phase space is provided by an idealized marathon race in which all runners travel at constant speed. At the start of the course, the density of runners is large, but they travel at a wide variety ...
pasta Jos´e A. Pons , Daniele Vigan`o and Nanda Rea
... It has long been hoped that stringent constraints could be placed on the equation of state of dense matter from astrophysical measurements of neutron stars, the compact remnants of the explosion of massive stars. Up to the present time, however, despite important breakthrough discoveries [1, 2, 3] ...
... It has long been hoped that stringent constraints could be placed on the equation of state of dense matter from astrophysical measurements of neutron stars, the compact remnants of the explosion of massive stars. Up to the present time, however, despite important breakthrough discoveries [1, 2, 3] ...
Magnetic fields generated by r-modes in accreting quark stars
... instability, the toroidal component of the field produces a new poloidal component as a result of its decay, which can then be wound up itself, closing the dynamo loop. When the differential rotation stops, the field can evolve into a stable configuration of a mixed poloidal-toroidal twisted-torus sh ...
... instability, the toroidal component of the field produces a new poloidal component as a result of its decay, which can then be wound up itself, closing the dynamo loop. When the differential rotation stops, the field can evolve into a stable configuration of a mixed poloidal-toroidal twisted-torus sh ...
L133 VERY LARGE TELESCOPE SPECTRA OF CARBON STARS
... In general, stars are oxygen-rich when they enter the AGB phase. Third dredge-up leads to 12C enrichment in the atmospheres of AGB stars. If the C/O ratio exceeds unity after the third dredge-up, the star is classified as a carbon star. Theoretical models have predicted that the amount of 12C enrich ...
... In general, stars are oxygen-rich when they enter the AGB phase. Third dredge-up leads to 12C enrichment in the atmospheres of AGB stars. If the C/O ratio exceeds unity after the third dredge-up, the star is classified as a carbon star. Theoretical models have predicted that the amount of 12C enrich ...
Star counts in the Galaxy-Simulating from very deep to very shallow
... Option (1) was the preferred one in the past, and the one adopted in some of the most successful Galaxy models. Despite their success in reproducing several sorts of data, it is not difficult to find points of inconsistency in many of such models. A common approximation, for instance, has been that ...
... Option (1) was the preferred one in the past, and the one adopted in some of the most successful Galaxy models. Despite their success in reproducing several sorts of data, it is not difficult to find points of inconsistency in many of such models. A common approximation, for instance, has been that ...
Spectral modeling of nebular-phase supernovae Anders Jerkstrand Department of Astronomy
... 2004et, analyzing its ultraviolet to mid-infrared evolution. Based on its Mg I] 4571 Å, Na I 5890, 5896 Å, [O I] 6300, 6364 Å, and [Ne II] 12.81 µ m nebular emission lines, we determine its progenitor mass to be around 15 M⊙ . We confirm that silicate dust, SiO, and CO have formed in the ejecta. Fin ...
... 2004et, analyzing its ultraviolet to mid-infrared evolution. Based on its Mg I] 4571 Å, Na I 5890, 5896 Å, [O I] 6300, 6364 Å, and [Ne II] 12.81 µ m nebular emission lines, we determine its progenitor mass to be around 15 M⊙ . We confirm that silicate dust, SiO, and CO have formed in the ejecta. Fin ...
Massive Stars in the Arches Cluster 12
... Given its extraordinary nature, the Arches cluster has been a target for many new observations. Stolte et al. (2002) recently verified a flat IMF slope for the Arches cluster, finding Γ = −0.8, using both adaptive optics imaging with the Gemini North telescope and the HST/NICMOS data presented in Fi ...
... Given its extraordinary nature, the Arches cluster has been a target for many new observations. Stolte et al. (2002) recently verified a flat IMF slope for the Arches cluster, finding Γ = −0.8, using both adaptive optics imaging with the Gemini North telescope and the HST/NICMOS data presented in Fi ...
SPY — The ESO Supernovae Type Ia Progenitor Survey
... dwarfs will, however, destroy themselves in a gigantic thermonuclear explosion. To do so, they have to be forced into a density and temperature regime, where carbon and oxygen burn explosively and disrupt the star. Above the Chandrasekhar mass (1.4 M) the electron degeneracy can no longer support w ...
... dwarfs will, however, destroy themselves in a gigantic thermonuclear explosion. To do so, they have to be forced into a density and temperature regime, where carbon and oxygen burn explosively and disrupt the star. Above the Chandrasekhar mass (1.4 M) the electron degeneracy can no longer support w ...
3D GR Hydrodynamic Simulations of Binary Neutron Star
... 1) Capture fluxes on coarse and fine grid AMR boundary 2) Integrate both until coarse and fine grid are aligned in time again 3) Restrict integrated coarse grid flux onto fine grid boundary 4) Difference between integrated coarse grid flux and fine grid flux is correction ...
... 1) Capture fluxes on coarse and fine grid AMR boundary 2) Integrate both until coarse and fine grid are aligned in time again 3) Restrict integrated coarse grid flux onto fine grid boundary 4) Difference between integrated coarse grid flux and fine grid flux is correction ...
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.