SN 2006gy: DISCOVERY OF THE MOST LUMINOUS
... O-type stars and WR stars have shown that their winds are highly clumped, requiring that their mass-loss rates through line-driven winds on the main sequence could be an order of magnitude lower than previously believed (Fullerton et al. 2006; Bouret et al. 2005). In that case, for stars with initia ...
... O-type stars and WR stars have shown that their winds are highly clumped, requiring that their mass-loss rates through line-driven winds on the main sequence could be an order of magnitude lower than previously believed (Fullerton et al. 2006; Bouret et al. 2005). In that case, for stars with initia ...
PPT (Download!) - SDSS SkyServer
... Give results table a name (for your MyDB) Give your query a name Wait until it says “started” ...
... Give results table a name (for your MyDB) Give your query a name Wait until it says “started” ...
Anisotropy of the Hectometer Cosmic Radio Background
... mined by local sources in the region whose radius r can be found from the condition κr . 1, where κ is the absorption coefficient of the radio waves. According to existing estimates for the diffuse interstellar medium, κ = 4 × 10–3 (f[MHz])–2.1 [pc–1]. In this case, the value of r, which may be call ...
... mined by local sources in the region whose radius r can be found from the condition κr . 1, where κ is the absorption coefficient of the radio waves. According to existing estimates for the diffuse interstellar medium, κ = 4 × 10–3 (f[MHz])–2.1 [pc–1]. In this case, the value of r, which may be call ...
Grade - Amazon S3
... Earthquakes usually occur where stress has been built up by plates moving in opposite directions against each other. Earthquakes cause waves (vibrations) which have: focus, the point below the surface where the quake begins epicenter, the point on the surface above the focus Energy released is measu ...
... Earthquakes usually occur where stress has been built up by plates moving in opposite directions against each other. Earthquakes cause waves (vibrations) which have: focus, the point below the surface where the quake begins epicenter, the point on the surface above the focus Energy released is measu ...
arXiv:astro-ph/0612072v1 4 Dec 2006 Theory of core
... the outer burning shells of the star, one speaks about the ‘prompt mechanism’. However, it appears as if the energy available to the shock is not sufficient, and the shock uses up its energy in the outer core mostly by the dissociation of heavy nuclei into nucleons. This change in composition result ...
... the outer burning shells of the star, one speaks about the ‘prompt mechanism’. However, it appears as if the energy available to the shock is not sufficient, and the shock uses up its energy in the outer core mostly by the dissociation of heavy nuclei into nucleons. This change in composition result ...
The importance of episodic accretion for low
... burst (third column); however, after this burst the disc cools sufficiently to undergo gravitational fragmentation; 2 low-mass stars form in the disc. ...
... burst (third column); however, after this burst the disc cools sufficiently to undergo gravitational fragmentation; 2 low-mass stars form in the disc. ...
Period-Luminosity Relations for delta Scuti Stars
... at visible bands: the amplitude of the variables is smaller, with which the mean magnitudes have lower dispersion; the interstellar extinction is lower (AK /AV ∼ 1/10); and the infrared luminosities are less sensitive to temperature changes (instability strip is narrower), so PL relations are tighte ...
... at visible bands: the amplitude of the variables is smaller, with which the mean magnitudes have lower dispersion; the interstellar extinction is lower (AK /AV ∼ 1/10); and the infrared luminosities are less sensitive to temperature changes (instability strip is narrower), so PL relations are tighte ...
The Nuclear Equation of State and Neutron Star Masses
... of radius. At extremely large radii (R 300 km), the mass starts to increase as configurations approach the white dwarf (WD) range (such configurations have much larger proton concentrations). Thus, there is a minimum stable mass for neutron stars, which is approximately 0.09 M (11), when R ∼ 200–3 ...
... of radius. At extremely large radii (R 300 km), the mass starts to increase as configurations approach the white dwarf (WD) range (such configurations have much larger proton concentrations). Thus, there is a minimum stable mass for neutron stars, which is approximately 0.09 M (11), when R ∼ 200–3 ...
the reality of the wolf 630 moving group - TigerPrints
... The concept of relic kinematic assemblages from dispersed stellar clusters has remained contentious since Eggen’s initial formulation of moving groups in the 1960’s. However, the availability of high quality parallaxes from the Hipparcos space astrometry mission has resulted in distance measurements ...
... The concept of relic kinematic assemblages from dispersed stellar clusters has remained contentious since Eggen’s initial formulation of moving groups in the 1960’s. However, the availability of high quality parallaxes from the Hipparcos space astrometry mission has resulted in distance measurements ...
The Spitzer/GLIMPSE Surveys - UW-Madison Astronomy
... In the early stages of producing the GLIMPSE image mosaics, it was discovered that there were a large number of extended objects that were especially bright in the 4.5 μm band of the IRAC detectors. These objects have been referred to by the GLIMPSE team as “green fuzzies” or extended green objects ...
... In the early stages of producing the GLIMPSE image mosaics, it was discovered that there were a large number of extended objects that were especially bright in the 4.5 μm band of the IRAC detectors. These objects have been referred to by the GLIMPSE team as “green fuzzies” or extended green objects ...
Evolution of Stars and Stellar Populations
... properties (i.e. evolution of effective temperatures, luminosities, surface chemical abundances) of stars, as a function of their initial mass and chemical composition. The next chapter describes the steps (often missing in stellar evolution books) necessary to transform the results from theoretical ...
... properties (i.e. evolution of effective temperatures, luminosities, surface chemical abundances) of stars, as a function of their initial mass and chemical composition. The next chapter describes the steps (often missing in stellar evolution books) necessary to transform the results from theoretical ...
Validation of Twelve Small Kepler Transiting Planets in the
... stars and to validate the signals. In the interim, three of them that are in systems with five candidates each (KOI0571.05 = Kepler-186 f, KOI-1422.04 = Kepler-296 f, and KOI-1422.05 = Kepler-296 e) were the subject of recent studies by others. KOI-1422.04 and KOI-1422.05 were announced as planets b ...
... stars and to validate the signals. In the interim, three of them that are in systems with five candidates each (KOI0571.05 = Kepler-186 f, KOI-1422.04 = Kepler-296 f, and KOI-1422.05 = Kepler-296 e) were the subject of recent studies by others. KOI-1422.04 and KOI-1422.05 were announced as planets b ...
The Chemical Composition of Exoplanet
... corresponding to the element of interest must be measured. Also, the continuum for a star must be properly normalized around a line before it can be accurately measured. The assumption of a specific solar composition is included in a reported stellar abundance. Adopting different solar abundances ca ...
... corresponding to the element of interest must be measured. Also, the continuum for a star must be properly normalized around a line before it can be accurately measured. The assumption of a specific solar composition is included in a reported stellar abundance. Adopting different solar abundances ca ...
Krypton in presolar mainstream SiC grains from AGB stars
... explain the high 130 Xe/82 Kr in fine grains. The results by Pignatari et al. (2004) seem to disagree with the second scenario. The Xe−G component in mainstream SiC grains does not agree with AGB models predictions at low metallicity (Z ≤ 1/3 Z ), because the (134 Xe/130 Xe)s ratio is too high with ...
... explain the high 130 Xe/82 Kr in fine grains. The results by Pignatari et al. (2004) seem to disagree with the second scenario. The Xe−G component in mainstream SiC grains does not agree with AGB models predictions at low metallicity (Z ≤ 1/3 Z ), because the (134 Xe/130 Xe)s ratio is too high with ...
VALIDATION OF TWELVE SMALL KEPLER TRANSITING PLANETS
... 1422.05 = Kepler-296 e) were the subject of recent studies by others. KOI-1422.04 and KOI-1422.05 were announced as planets by Lissauer et al. (2014) and Rowe et al. (2014) using their statistical framework for validation of multis “in bulk”, though only the first was mentioned as being in the HZ. K ...
... 1422.05 = Kepler-296 e) were the subject of recent studies by others. KOI-1422.04 and KOI-1422.05 were announced as planets by Lissauer et al. (2014) and Rowe et al. (2014) using their statistical framework for validation of multis “in bulk”, though only the first was mentioned as being in the HZ. K ...
and galaxies
... Thin disk is metal-rich, [Fe/H]~0, star formation, lots of young blue stars. Around 325 parsec region of sun. Thick disk, metal-poor [Fe/H]~-0.5, older stars. Disk thickness increases towards the inner regions of galaxy.Gas/dust in disk absorbs visible light, but 21cm H-I line ok. Thus, radiotelesco ...
... Thin disk is metal-rich, [Fe/H]~0, star formation, lots of young blue stars. Around 325 parsec region of sun. Thick disk, metal-poor [Fe/H]~-0.5, older stars. Disk thickness increases towards the inner regions of galaxy.Gas/dust in disk absorbs visible light, but 21cm H-I line ok. Thus, radiotelesco ...
The star formation history of galaxies in 3D: CALIFA perspective
... One step to understand how galaxies form and evolve is classifying galaxies and studying their properties. Most of the massive galaxies in the near Universe are E, S0 and spirals (Blanton & Moustakas 2009), following well the Hubble tuning-fork diagram. The bulge fraction seems to be one of the main ...
... One step to understand how galaxies form and evolve is classifying galaxies and studying their properties. Most of the massive galaxies in the near Universe are E, S0 and spirals (Blanton & Moustakas 2009), following well the Hubble tuning-fork diagram. The bulge fraction seems to be one of the main ...
H 2 O, OH, SiO, NH 3 and CH 3 OH
... [proh-toh-stahr] an early stage in the evolution of a star, after the beginning of the collapse of the gas cloud from which it is formed, but before sufficient contraction has occurred to permit initiation of nuclear reactions at its core. ...
... [proh-toh-stahr] an early stage in the evolution of a star, after the beginning of the collapse of the gas cloud from which it is formed, but before sufficient contraction has occurred to permit initiation of nuclear reactions at its core. ...
the origin of binary stars - Institut d`Astronomie et d`Astrophysique
... In this way, observationally identifiable “molecular cloud cores” are formed. Stage II: The star formation process begins in earnest when a condensing cloud core “passes the brink of instability” (Shu et al. 1987) and collapses dynamically toward stellar densities. This leads to the formation of a c ...
... In this way, observationally identifiable “molecular cloud cores” are formed. Stage II: The star formation process begins in earnest when a condensing cloud core “passes the brink of instability” (Shu et al. 1987) and collapses dynamically toward stellar densities. This leads to the formation of a c ...
The rebirth of Supernova 1987A a study of the ejecta-ring collision
... also the first ones to suggest that SNe were results of the great energy release of collapsing stars (Baade & Zwicky 1934). The idea of the collapsing core of the star is today the accepted model for many, but not for all SN events. Hoyle & Fowler proposed in 1960 an alternative scenario for the exp ...
... also the first ones to suggest that SNe were results of the great energy release of collapsing stars (Baade & Zwicky 1934). The idea of the collapsing core of the star is today the accepted model for many, but not for all SN events. Hoyle & Fowler proposed in 1960 an alternative scenario for the exp ...
Follow-up observations of extremely metal
... extremely rare as illustrates the fact that, despite substantial efforts, only 4 stars are known at [Fe/H]< −5. Theoretical calculations show that the lack of metals in the gas in the early universe prevents gas clouds from fragmenting effectively, and shifts the initial mass function to very high m ...
... extremely rare as illustrates the fact that, despite substantial efforts, only 4 stars are known at [Fe/H]< −5. Theoretical calculations show that the lack of metals in the gas in the early universe prevents gas clouds from fragmenting effectively, and shifts the initial mass function to very high m ...
A CHANDRA X-RAY STUDY OF THE DENSE GLOBULAR CLUSTER TERZAN... C. O. Heinke, P. D. Edmonds, J. E. Grindlay, and...
... from the corrected position of EXO 1745248. A combination of this star and another star just above it (star B) was shown in the cleaned CMD of EGC01 (their Fig. 8) as one of only two stars that lie more than 3 to the blue from the distribution of stars in that color-magnitude diagram. Our attempt ...
... from the corrected position of EXO 1745248. A combination of this star and another star just above it (star B) was shown in the cleaned CMD of EGC01 (their Fig. 8) as one of only two stars that lie more than 3 to the blue from the distribution of stars in that color-magnitude diagram. Our attempt ...
Tidal interaction of a rotating 1 vec {M_sun} star with a - UvA-DARE
... by the non-resonant dynamical tide. To explain the observed Pcirc would require a viscosity that is '50 times larger than predicted by simple mixing length estimates. Goodman & Dickson (1998), in their WKB treatment of dynamical tides, considered non-linear damping of excited g-modes near the stella ...
... by the non-resonant dynamical tide. To explain the observed Pcirc would require a viscosity that is '50 times larger than predicted by simple mixing length estimates. Goodman & Dickson (1998), in their WKB treatment of dynamical tides, considered non-linear damping of excited g-modes near the stella ...
Star Formation and Young Clusters in Cygnus
... plane between longitudes 67◦ and 100◦ . The Great Cygnus Rift is most prominent to the right, and the 10 degree large Cygnus X region provides the highest extinction in the whole field. The North America nebula is indicated. At higher longitudes one finds the large cloud Kh 141 = TGU 541 associated ...
... plane between longitudes 67◦ and 100◦ . The Great Cygnus Rift is most prominent to the right, and the 10 degree large Cygnus X region provides the highest extinction in the whole field. The North America nebula is indicated. At higher longitudes one finds the large cloud Kh 141 = TGU 541 associated ...
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.