![Fossil Galaxies](http://s1.studyres.com/store/data/017866916_1-a73789d37abd011c62ad3a5a3cf1441a-300x300.png)
Fossil Galaxies
... and stars. In ultra-faint dwarf galaxies, dark matter outweighs ordinary matter by at least a factor of 100. Because their gas was expelled and their star formation quenched, the small galaxies in Brown’s study are made up of mostly dark matter. Thus, these dark-matter islands where dwarf galaxies f ...
... and stars. In ultra-faint dwarf galaxies, dark matter outweighs ordinary matter by at least a factor of 100. Because their gas was expelled and their star formation quenched, the small galaxies in Brown’s study are made up of mostly dark matter. Thus, these dark-matter islands where dwarf galaxies f ...
Circumstellar medium around rotating massive stars at solar metallicity
... identical to a spherical mesh with an equidistant angle discretisation and a logarithmic radial discretisation. With this mesh, the self-similar evolution phase of the bubble is well recovered, demonstrating the suitability of the chosen approach for the astrophysical problem under consideration (se ...
... identical to a spherical mesh with an equidistant angle discretisation and a logarithmic radial discretisation. With this mesh, the self-similar evolution phase of the bubble is well recovered, demonstrating the suitability of the chosen approach for the astrophysical problem under consideration (se ...
Oxygen isotopes in circumstellar Al_2O_3 grains from meteorites
... The Al 20 3 grains exhibit a range in 16 0/ 18 0 that is larger than predicted for a suite of stars with the same starting composition (Fig. 3). The predicted range in 160/ 18 0 does not increase significantly for stars up to ~15M 0 (Dearborn 1992; El Eid 1994; Boothroyd et al. 1994). Thus, a differ ...
... The Al 20 3 grains exhibit a range in 16 0/ 18 0 that is larger than predicted for a suite of stars with the same starting composition (Fig. 3). The predicted range in 160/ 18 0 does not increase significantly for stars up to ~15M 0 (Dearborn 1992; El Eid 1994; Boothroyd et al. 1994). Thus, a differ ...
CNO and F abundances in the barium star HD 123396
... abundance of [Fe/H]1 ≈ −1, and is the most metal-deficient barium star from the Allen & Barbuy (2006) sample. The low metallicity of HD 123396 makes it unique among barium stars as it is right at the low end of the barium star metallicity distribution, and at a metallicity that encompasses the metal ...
... abundance of [Fe/H]1 ≈ −1, and is the most metal-deficient barium star from the Allen & Barbuy (2006) sample. The low metallicity of HD 123396 makes it unique among barium stars as it is right at the low end of the barium star metallicity distribution, and at a metallicity that encompasses the metal ...
the paper - Universitäts
... of He 2-131 (middle), since its mass loss rate is obviously too small, as evidenced by the presence of almost only purely photospheric lines hardly influenced by the thin wind – indicating that this CSPN must have a much larger luminosity, because L is the major factor determining the mass loss rate ...
... of He 2-131 (middle), since its mass loss rate is obviously too small, as evidenced by the presence of almost only purely photospheric lines hardly influenced by the thin wind – indicating that this CSPN must have a much larger luminosity, because L is the major factor determining the mass loss rate ...
Pulsations in White Dwarfs
... Extremely rare (14 / 25,000) carbonatmosphere white dwarfs discovered in 2007 only. They bunch around Teff~20,000 K and have very high surface gravities. They are likely all highly magnetic (>1 MGauss) and half them pulsate. Low-degree (1,2), low- to mid-order g-mode ...
... Extremely rare (14 / 25,000) carbonatmosphere white dwarfs discovered in 2007 only. They bunch around Teff~20,000 K and have very high surface gravities. They are likely all highly magnetic (>1 MGauss) and half them pulsate. Low-degree (1,2), low- to mid-order g-mode ...
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 ...
Discovery probability of transiting extragalactic planets and
... presence of the planet. The radius of the star’s orbit around the center of mass is so small(due to the greater mass) consequently the velocity of the star around the system’s center of mass is much smaller than that of the planet. However, velocity variations down to 0.5 m/s or even somewhat less c ...
... presence of the planet. The radius of the star’s orbit around the center of mass is so small(due to the greater mass) consequently the velocity of the star around the system’s center of mass is much smaller than that of the planet. However, velocity variations down to 0.5 m/s or even somewhat less c ...
The SOPHIE search for northern extrasolar planets
... Wright et al. (2012), indicating the frequency of stars that harbour close-in massive planets – also called hot Jupiters: Mayor et al. (2011) reported a value of 0.89 ± 0.36% for the occurrence of planets more massive than 50 M⊕ that have periods shorter than 11 days, Howard et al. (2010) found an o ...
... Wright et al. (2012), indicating the frequency of stars that harbour close-in massive planets – also called hot Jupiters: Mayor et al. (2011) reported a value of 0.89 ± 0.36% for the occurrence of planets more massive than 50 M⊕ that have periods shorter than 11 days, Howard et al. (2010) found an o ...
the evil-mc model for ellipsoidal variations of planet
... Analysis of ellipsoidal variations and eclipses has a long history for close binary stars, where it provides a wealth of information regarding stellar masses, luminosities, and internal structures, among other properties (Kopal 1959). The effects of tides in such systems (tidal distortions, thermal ...
... Analysis of ellipsoidal variations and eclipses has a long history for close binary stars, where it provides a wealth of information regarding stellar masses, luminosities, and internal structures, among other properties (Kopal 1959). The effects of tides in such systems (tidal distortions, thermal ...
NAAP 3 of 7 Determining Astronomical Distance
... http://astro.unl.edu/naap/distance/animations/parallaxExplorer.html ...
... http://astro.unl.edu/naap/distance/animations/parallaxExplorer.html ...
The Mass-loss Rate of Red Supergiant
... driven winds around AGB stars and RSGs. The spectral energy distribution of the source can be specified ...
... driven winds around AGB stars and RSGs. The spectral energy distribution of the source can be specified ...
Circum-stellar medium around rotating massive stars at solar
... For this study, we used a specific map which results in a mesh identical to a spherical mesh with an equidistant angle discretisation and a logarithmic radial discretisation. With this mesh, the self-similar evolution phase of the bubble is well recovered, demonstrating the suitability of the chosen ...
... For this study, we used a specific map which results in a mesh identical to a spherical mesh with an equidistant angle discretisation and a logarithmic radial discretisation. With this mesh, the self-similar evolution phase of the bubble is well recovered, demonstrating the suitability of the chosen ...
Abundance Trends of Alpha and Fe
... would have had large [α/Fe] ratios that are seen in the “second-generation” halo stars that are observed today. The exceptions to the Ca overabundance trend at low metallicity may be more interesting than they were in the case of Ni. Ignoring the point of NGC 4833 from a relatively old study involvi ...
... would have had large [α/Fe] ratios that are seen in the “second-generation” halo stars that are observed today. The exceptions to the Ca overabundance trend at low metallicity may be more interesting than they were in the case of Ni. Ignoring the point of NGC 4833 from a relatively old study involvi ...
Mass segregation in star clusters is not energy equipartition
... profiles. If open clusters formed from initial conditions similar to observed star-forming regions, we therefore would not expect any energy equipartition to occur through dynamical evolution. We repeated the simulations without stellar evolution and find similar results; the most massive stars sink ...
... profiles. If open clusters formed from initial conditions similar to observed star-forming regions, we therefore would not expect any energy equipartition to occur through dynamical evolution. We repeated the simulations without stellar evolution and find similar results; the most massive stars sink ...
30.4 Gravitational collapse & early protostellar evolution I (HB)
... “Mass-gaining star deriving most of its luminosity from accretion.” (However, caution for massive stars.) ...
... “Mass-gaining star deriving most of its luminosity from accretion.” (However, caution for massive stars.) ...
A double detached shell around a post
... similar to the well-studied object IRC +10420. Our mid-infrared images of IRAS 17163 are the first direct images of this bright midinfrared source. These images clearly show a double dusty detached shell around the central star, caused by successive ejections of material on a timescale of the order ...
... similar to the well-studied object IRC +10420. Our mid-infrared images of IRAS 17163 are the first direct images of this bright midinfrared source. These images clearly show a double dusty detached shell around the central star, caused by successive ejections of material on a timescale of the order ...
SOUTHERN CONSTELLATION, SEXTANS Sextans constellation
... and is approximately 287 light years distant from Earth. It is the brightest star in Sextans. It is 122 times more luminous than the Sun and has a mass three times solar. The star is believed to be about 300 million years old. It is informally considered to be an “equator star,” currently located le ...
... and is approximately 287 light years distant from Earth. It is the brightest star in Sextans. It is 122 times more luminous than the Sun and has a mass three times solar. The star is believed to be about 300 million years old. It is informally considered to be an “equator star,” currently located le ...
Galaxy Properties - Tufts Institute of Cosmology
... Ellipticals: Velocities of stars in ellipticals are more or less random Velocity dispersions are responsible for the overall shape of galaxies. Oblate and Prolate Ellipticals – how that? Spiral: Velocities of stars in spirals are more ordered. Stars rotate around the galactic center in a disk surrou ...
... Ellipticals: Velocities of stars in ellipticals are more or less random Velocity dispersions are responsible for the overall shape of galaxies. Oblate and Prolate Ellipticals – how that? Spiral: Velocities of stars in spirals are more ordered. Stars rotate around the galactic center in a disk surrou ...
Observations with Herschel: High-mass star formation and the
... Along the Milky-Way’s spiral arms, the dynamic interstellar medium is stretched out and sprinkled with new born stars. In this ever changing environment, galactic evolution takes place. It is an unusual chemical and physical laboratory, characterized by very low densities and temperatures not availa ...
... Along the Milky-Way’s spiral arms, the dynamic interstellar medium is stretched out and sprinkled with new born stars. In this ever changing environment, galactic evolution takes place. It is an unusual chemical and physical laboratory, characterized by very low densities and temperatures not availa ...
Neutron stars - Institut de Physique Nucleaire de Lyon
... Physikalische Zs. Sowjetunion 1 (1932) 285]: for stars with M>1.5M☼ “density of matter becomes so great that atomic nuclei come in close contact, foming one gigantic nucleus’’. J.Chadwick – discovery of a neutron [Nature, Feb.27, 1932] W.Baade & F.Zwicky (1933) – prediction of neutron stars [“Su ...
... Physikalische Zs. Sowjetunion 1 (1932) 285]: for stars with M>1.5M☼ “density of matter becomes so great that atomic nuclei come in close contact, foming one gigantic nucleus’’. J.Chadwick – discovery of a neutron [Nature, Feb.27, 1932] W.Baade & F.Zwicky (1933) – prediction of neutron stars [“Su ...
What powers luminous infrared galaxies?
... other hand, often resemble narrow line active galactic nuclei (AGNs), with a few broad line examples. Some of them contain compact radio nuclei, again indicative of hidden AGNs. However, being reprocessed radiation, the far-infrared and radio continuum are not very specific with respect to the natur ...
... other hand, often resemble narrow line active galactic nuclei (AGNs), with a few broad line examples. Some of them contain compact radio nuclei, again indicative of hidden AGNs. However, being reprocessed radiation, the far-infrared and radio continuum are not very specific with respect to the natur ...
Planetary nebula
![](https://commons.wikimedia.org/wiki/Special:FilePath/NGC6543.jpg?width=300)
A planetary nebula, often abbreviated as PN or plural PNe, is a kind of emission nebula consisting of an expanding glowing shell of ionized gas ejected from old red giant stars late in their lives. The word ""nebula"" is Latin for mist or cloud and the term ""planetary nebula"" is a misnomer that originated in the 1780s with astronomer William Herschel because when viewed through his telescope, these objects appeared to him to resemble the rounded shapes of planets. Herschel's name for these objects was popularly adopted and has not been changed. They are a relatively short-lived phenomenon, lasting a few tens of thousands of years, compared to a typical stellar lifetime of several billion years.A mechanism for formation of most planetary nebulae is thought to be the following: at the end of the star's life, during the red giant phase, the outer layers of the star are expelled by strong stellar winds. Eventually, after most of the red giant's atmosphere is dissipated, the exposed hot, luminous core emits ultraviolet radiation to ionize the ejected outer layers of the star. Absorbed ultraviolet light energises the shell of nebulous gas around the central star, appearing as a bright coloured planetary nebula at several discrete visible wavelengths.Planetary nebulae may play a crucial role in the chemical evolution of the Milky Way, returning material to the interstellar medium from stars where elements, the products of nucleosynthesis (such as carbon, nitrogen, oxygen and neon), have been created. Planetary nebulae are also observed in more distant galaxies, yielding useful information about their chemical abundances.In recent years, Hubble Space Telescope images have revealed many planetary nebulae to have extremely complex and varied morphologies. About one-fifth are roughly spherical, but the majority are not spherically symmetric. The mechanisms which produce such a wide variety of shapes and features are not yet well understood, but binary central stars, stellar winds and magnetic fields may play a role.