astrophysics - The University of Sydney
... The cycle then repeats itself. Helium is fused to carbon and oxygen in the star’s core, but eventually the core runs out of helium. Fusion stops, and the core resumes its collapse. This heats up the layer of helium just outside the core, which begins fusing in a shell of its own, inside the hydrogen ...
... The cycle then repeats itself. Helium is fused to carbon and oxygen in the star’s core, but eventually the core runs out of helium. Fusion stops, and the core resumes its collapse. This heats up the layer of helium just outside the core, which begins fusing in a shell of its own, inside the hydrogen ...
Sub-luminous type Ia supernovae from the mergers of equal
... result in SNe Ia, but may be observable as faint short-lived transients. In contrast, more massive mergers will be brighter but much rarer owing to the paucity of high-mass white dwarfs. We used the results of recent population synthesis studies 21 computed with the StarTrack code22,23 to predict th ...
... result in SNe Ia, but may be observable as faint short-lived transients. In contrast, more massive mergers will be brighter but much rarer owing to the paucity of high-mass white dwarfs. We used the results of recent population synthesis studies 21 computed with the StarTrack code22,23 to predict th ...
A Supermassive Black Hole in the Andromeda Galaxy
... If the MDO is made of any of the above brown dwarfs, collisions easily convert them into gas in «1010 yr. ...
... If the MDO is made of any of the above brown dwarfs, collisions easily convert them into gas in «1010 yr. ...
S E D
... observations do /theory the higher mass, the shorter their main sequence gets, fig.13.1. By EQ 13.5 we see that an estimate for the isochrones is not even that bad. At fig.13.4, we see an isochrones suddenly jumping from 1.2 – 1.25, and this is due to the convective core, and as you see the isochr ...
... observations do /theory the higher mass, the shorter their main sequence gets, fig.13.1. By EQ 13.5 we see that an estimate for the isochrones is not even that bad. At fig.13.4, we see an isochrones suddenly jumping from 1.2 – 1.25, and this is due to the convective core, and as you see the isochr ...
microlensing binaries with candidate brown dwarf companions
... Among these two cases, the microlensing brown dwarf discovered by Gould et al. (2009) is the exception that provides the rule because the lens mass could be determined not by measuring the lens parallax induced by Earth’s orbital motion but from the “terrestrial parallax.” ...
... Among these two cases, the microlensing brown dwarf discovered by Gould et al. (2009) is the exception that provides the rule because the lens mass could be determined not by measuring the lens parallax induced by Earth’s orbital motion but from the “terrestrial parallax.” ...
Astrophysics in a Nutshell, Second Edition
... At the same time, hydrogen continues to burn in a shell surrounding the core. When helium ignition begins, the star moves quickly on the H-R diagram to the left side of the horizontal branch, and then evolves more slowly to the right along this branch, as seen in Fig. 4.1. Stars with higher initial ...
... At the same time, hydrogen continues to burn in a shell surrounding the core. When helium ignition begins, the star moves quickly on the H-R diagram to the left side of the horizontal branch, and then evolves more slowly to the right along this branch, as seen in Fig. 4.1. Stars with higher initial ...
Polarimetric evidence of a white dwarf pulsar in
... dwarf spin and the beat periods, are also consistent with this emission being produced in the white dwarf magnetosphere, which is additionally modulated at the binary period. The spectral energy distribution (SED) in AR Sco (2, 21) shows a Sν ∝ ν α1 (α1 ∼ 1.3) self-absorbed power law spectral distri ...
... dwarf spin and the beat periods, are also consistent with this emission being produced in the white dwarf magnetosphere, which is additionally modulated at the binary period. The spectral energy distribution (SED) in AR Sco (2, 21) shows a Sν ∝ ν α1 (α1 ∼ 1.3) self-absorbed power law spectral distri ...
Interacting Binary Star System Activity
... A light curve graphs the intensity or brightness of light that comes from an object in space, as a function of time. The “magnitude versus location” graphs made by students in this activity are very similar if the orbiting star location is equated to time, which it can be since the data was taken at ...
... A light curve graphs the intensity or brightness of light that comes from an object in space, as a function of time. The “magnitude versus location” graphs made by students in this activity are very similar if the orbiting star location is equated to time, which it can be since the data was taken at ...
BINARY STARS
... true that we can obtain much information from the starlight collected from telescopes. We can analyse the chemical composition, the surface temperature, the velocity and the distance, and so on. However, none of these directly reveals the masses of stars. To measure their masses, we must see their g ...
... true that we can obtain much information from the starlight collected from telescopes. We can analyse the chemical composition, the surface temperature, the velocity and the distance, and so on. However, none of these directly reveals the masses of stars. To measure their masses, we must see their g ...
Chemical Signatures in Dwarf Galaxies
... can come from H ii region emission lines, planetary nebulae, or supernova remnants, but mostly they come from stars. Since stars can live a very long time, for example, a 0.8 MA star born at the time of the Big Bang would only now be ascending the red giant branch, and, if, for the most part, its qu ...
... can come from H ii region emission lines, planetary nebulae, or supernova remnants, but mostly they come from stars. Since stars can live a very long time, for example, a 0.8 MA star born at the time of the Big Bang would only now be ascending the red giant branch, and, if, for the most part, its qu ...
Evolution and colors of helium-core white dwarf stars with high
... captured the attention of researchers since Kippenhahn et al. (1967) suggested that these stars could be the natural result of substantial mass loss from low-mass red giant stars filling their Roche lobes in binary systems. Later, Webbink (1975) was the first to show that for masses greater than 0.1 ...
... captured the attention of researchers since Kippenhahn et al. (1967) suggested that these stars could be the natural result of substantial mass loss from low-mass red giant stars filling their Roche lobes in binary systems. Later, Webbink (1975) was the first to show that for masses greater than 0.1 ...
Study properties of dwarf galaxies in and around the nearby Lynx
... objects and populated by dwarfs. The galaxy densities and other parameters vary significantly from one void to another. One expects that not only galaxy interactions occur in voids much less frequently, but also DM halo and galaxy formation from density perturbations can be somewhat retarded due to ...
... objects and populated by dwarfs. The galaxy densities and other parameters vary significantly from one void to another. One expects that not only galaxy interactions occur in voids much less frequently, but also DM halo and galaxy formation from density perturbations can be somewhat retarded due to ...
HOW TO MAKE A SINGLETON sdB STAR VIA ACCELERATED STELLAR... Drew Clausen and Richard A. Wade
... This formation channel depends on several assumptions made in modeling binary stellar evolution. The initial configuration of the binary must be such that the primary evolves to the giant branch and triggers an episode of unstable mass transfer that completely removes its envelope before the merger. ...
... This formation channel depends on several assumptions made in modeling binary stellar evolution. The initial configuration of the binary must be such that the primary evolves to the giant branch and triggers an episode of unstable mass transfer that completely removes its envelope before the merger. ...
Adiabatic evolution of mass-losing stars
... with error <3 per cent, where ρ̃ is the dimensionless stellar mean density in terms of the initial mean density of the star and m̃ is the remaining stellar mass in terms of the solar mass. The Sun becomes denser in the initial phase of mass transfer, so its orbital period decreases, which means that ...
... with error <3 per cent, where ρ̃ is the dimensionless stellar mean density in terms of the initial mean density of the star and m̃ is the remaining stellar mass in terms of the solar mass. The Sun becomes denser in the initial phase of mass transfer, so its orbital period decreases, which means that ...
The potential of the variable DA white dwarf G117–B15A as
... when axion losses are taken into account. AGB stars are supposed to be the progenitors of white dwarfs and, therefore, white dwarfs are as well excellent candidates to test the existence of several weakly interacting massive particles. This was recognized early by several authors (see, for instance ...
... when axion losses are taken into account. AGB stars are supposed to be the progenitors of white dwarfs and, therefore, white dwarfs are as well excellent candidates to test the existence of several weakly interacting massive particles. This was recognized early by several authors (see, for instance ...
Accretion of brown dwarfs
... - positive correlation between rotation period and mass - rotational evolution determined by contraction + winds - change of dynamo in very low mass regime 2. Spectroscopic variability: close-up view on accretion behaviour - strong accretion rate variations in stars and brown dwarfs - evidence for a ...
... - positive correlation between rotation period and mass - rotational evolution determined by contraction + winds - change of dynamo in very low mass regime 2. Spectroscopic variability: close-up view on accretion behaviour - strong accretion rate variations in stars and brown dwarfs - evidence for a ...
The evolution of helium rich subdwarf B stars
... • Subdwarf B stars form the dominant population of faint blue blue stars (mB ~ 16) in our galaxy and giant elliptical galaxies • They are 0.5 MSun core helium-burning stars • Progenitors of White Dwarfs • Evolution has been the subject of much debate although evolution is though to play an important ...
... • Subdwarf B stars form the dominant population of faint blue blue stars (mB ~ 16) in our galaxy and giant elliptical galaxies • They are 0.5 MSun core helium-burning stars • Progenitors of White Dwarfs • Evolution has been the subject of much debate although evolution is though to play an important ...
PPT
... The high metallicity of this cluster makes these effects much more important. To this end, we have followed the entire evolution of 0.5249, 0.5701, 0.593, 0.6096, 0.6323, 0.6598 and 0.7051 M white dwarf sequences which include both physical processes. Our sequences start from stellar models o ...
... The high metallicity of this cluster makes these effects much more important. To this end, we have followed the entire evolution of 0.5249, 0.5701, 0.593, 0.6096, 0.6323, 0.6598 and 0.7051 M white dwarf sequences which include both physical processes. Our sequences start from stellar models o ...
CHP 14
... a. they conserved angular momentum when they collapsed. b. they have high orbital velocities. c. they have high densities. d. they have high temperatures. e. the energy from the supernova explosion that formed them made them spin faster. 3. Although neutron stars are very hot, they are not easy to l ...
... a. they conserved angular momentum when they collapsed. b. they have high orbital velocities. c. they have high densities. d. they have high temperatures. e. the energy from the supernova explosion that formed them made them spin faster. 3. Although neutron stars are very hot, they are not easy to l ...
Neutron Stars and Black Holes
... a. they conserved angular momentum when they collapsed. b. they have high orbital velocities. c. they have high densities. d. they have high temperatures. e. the energy from the supernova explosion that formed them made them spin faster. 3. Although neutron stars are very hot, they are not easy to l ...
... a. they conserved angular momentum when they collapsed. b. they have high orbital velocities. c. they have high densities. d. they have high temperatures. e. the energy from the supernova explosion that formed them made them spin faster. 3. Although neutron stars are very hot, they are not easy to l ...
The California Planet Survey II. A Saturn
... nitudes are plotted in the second panel of Figure 4 at the same magnitude scale as the top panel. The check star is HD 153897 (V = 6.57, B − V = 0.43, F4V). The yearly means of the K − C measurements have a range of only 0.0016 mag; their standard deviation is only 0.0007 mag. The standard deviation ...
... nitudes are plotted in the second panel of Figure 4 at the same magnitude scale as the top panel. The check star is HD 153897 (V = 6.57, B − V = 0.43, F4V). The yearly means of the K − C measurements have a range of only 0.0016 mag; their standard deviation is only 0.0007 mag. The standard deviation ...
Maximum Mass Limit of Stars on the Main Sequence
... Bonnell presents 3D simulations of stellar mass growth by competitive accretion in small young clusters. In this method, growth is promoted by the size and composition of the stars accretion domain. As mass increases, the gravitational reach increases as well. This implies that stars that are born i ...
... Bonnell presents 3D simulations of stellar mass growth by competitive accretion in small young clusters. In this method, growth is promoted by the size and composition of the stars accretion domain. As mass increases, the gravitational reach increases as well. This implies that stars that are born i ...
Hot Stars With Cool Companions
... not be resolvable by current imaging systems are likely to have the largest impact on planet formation, a spectroscopic multiplicity survey of nearby intermediate-mass stars is needed. The multiplicity of A- and B-type stars can also help constrain the binary star formation mechanism and the relevan ...
... not be resolvable by current imaging systems are likely to have the largest impact on planet formation, a spectroscopic multiplicity survey of nearby intermediate-mass stars is needed. The multiplicity of A- and B-type stars can also help constrain the binary star formation mechanism and the relevan ...
In Pursuit of the Least Luminous Galaxies
... extrapolation of the known population to predict a total number of ∼100–500 dwarf satellites [14, 15]. Uniform: because the very least luminous MW dwarfs (MV ∼ −2) can currently only be found within 50 kpc, it is presently unclear whether dwarfs can form with such intrinsically low luminosities, or ...
... extrapolation of the known population to predict a total number of ∼100–500 dwarf satellites [14, 15]. Uniform: because the very least luminous MW dwarfs (MV ∼ −2) can currently only be found within 50 kpc, it is presently unclear whether dwarfs can form with such intrinsically low luminosities, or ...