Stellar Population Effects on the Inferred Photon Density at
... only approximately 25 per cent of binary systems survive the first supernova. The models in use here comprise version 2.0 of the bpass model dataset. We employ stellar evolution and atmosphere models with a metallicity mass fraction ranging from Z = 0.001 to 0.040. These metallicities correspond to o ...
... only approximately 25 per cent of binary systems survive the first supernova. The models in use here comprise version 2.0 of the bpass model dataset. We employ stellar evolution and atmosphere models with a metallicity mass fraction ranging from Z = 0.001 to 0.040. These metallicities correspond to o ...
WASP-35b, WASP-48b, AND HAT-P-30b/WASP
... such that planets very close to their host stars have circular orbits while those farther from the stars show a wide range of eccentricities, seems to provide evidence for the tidal circularization of planetary orbits (Mazeh 2008). However, it had generally been assumed that the masses of planets ar ...
... such that planets very close to their host stars have circular orbits while those farther from the stars show a wide range of eccentricities, seems to provide evidence for the tidal circularization of planetary orbits (Mazeh 2008). However, it had generally been assumed that the masses of planets ar ...
arXiv:astro-ph/0701792v1 29 Jan 2007
... that there is no solution satisfying the equations if the ratio of the central gas density to the central dark matter density is larger than certain threshold value. Above such threshold value, any additional mass added to the combined components of gas and dark matter will make the whole system uns ...
... that there is no solution satisfying the equations if the ratio of the central gas density to the central dark matter density is larger than certain threshold value. Above such threshold value, any additional mass added to the combined components of gas and dark matter will make the whole system uns ...
The Central Star Candidate of the Planetary Nebula Sh2
... which is mounted on the 2.5-m Isaac Newton Telescope (INT) on La Palma in the Canary Islands. The images were processed in the usual way using theli, fits liberator and matlab to produce the RGB image shown in Fig. 1. The three photometric datasets of the ∼13.5-mag central star candidate CS1, presen ...
... which is mounted on the 2.5-m Isaac Newton Telescope (INT) on La Palma in the Canary Islands. The images were processed in the usual way using theli, fits liberator and matlab to produce the RGB image shown in Fig. 1. The three photometric datasets of the ∼13.5-mag central star candidate CS1, presen ...
Chapter 6 in the LSST Science Book
... have begun bound to one another, and both may be on their first approach to the Milky Way, not already bound to it. Attempts to model the motion of the Clouds together with a formation model for the Magellanic Stream in light of the new data (e.g., Besla et al. 2009) are very much works in progress. ...
... have begun bound to one another, and both may be on their first approach to the Milky Way, not already bound to it. Attempts to model the motion of the Clouds together with a formation model for the Magellanic Stream in light of the new data (e.g., Besla et al. 2009) are very much works in progress. ...
GOMOS data characterisation and error estimation
... and 926–952 nm with 0.2 nm resolution. Two photometers that are located at blue (473–527 nm) and red (646–698 nm) measure the stellar flux through the atmosphere at a sampling frequency of 1 kHz. By August 2009 GOMOS had observed about 668 000 stellar occultations. An overview of the GOMOS instrumen ...
... and 926–952 nm with 0.2 nm resolution. Two photometers that are located at blue (473–527 nm) and red (646–698 nm) measure the stellar flux through the atmosphere at a sampling frequency of 1 kHz. By August 2009 GOMOS had observed about 668 000 stellar occultations. An overview of the GOMOS instrumen ...
The Milky Way and Andromeda galaxies in a constrained
... imprints of the formation of the LG on their final properties. In particular, we focus on the formation of the main stellar components of the galaxies, and investigate possible correlations between the formation of stellar discs and large-scale effects such as merger events and misalignment between t ...
... imprints of the formation of the LG on their final properties. In particular, we focus on the formation of the main stellar components of the galaxies, and investigate possible correlations between the formation of stellar discs and large-scale effects such as merger events and misalignment between t ...
Probing the Dark Matter Content of Local Group Dwarf Spheroidal
... to attract much attention in recent years. The first evidence of this emerged in 1983, when Aaronson published velocity measurements of three carbon stars in the Draco dSph. These data implied a velocity dispersion for Draco of 6.5 km/s, from which Aaronson cautiously inferred a mass-to-slight ratio ...
... to attract much attention in recent years. The first evidence of this emerged in 1983, when Aaronson published velocity measurements of three carbon stars in the Draco dSph. These data implied a velocity dispersion for Draco of 6.5 km/s, from which Aaronson cautiously inferred a mass-to-slight ratio ...
The Lagoon Nebula and its Vicinity
... cluster, so NGC 6530 is now always used to refer to the cluster rather than any surrounding nebulosity. We take NGC 6533 to refer to the H II region only, comprising NGC 6523 and 6526. H II region studies have generally concentrated on the brighter eastern core (i.e. NGC 6523), and so it is this des ...
... cluster, so NGC 6530 is now always used to refer to the cluster rather than any surrounding nebulosity. We take NGC 6533 to refer to the H II region only, comprising NGC 6523 and 6526. H II region studies have generally concentrated on the brighter eastern core (i.e. NGC 6523), and so it is this des ...
banff04
... higher accretion rates and mass outflow rates (e.g. Pudritz 1985). • Disk photo-evaporation could create a low-velocity disk outflow (e.g. Hollenbach et al. 1994; Yorke & Welz 1996). • Radiation pressure higher for dusty gas (e.g. Wolfire & Cassinelli 1987), may contribute to flow acceleration and a ...
... higher accretion rates and mass outflow rates (e.g. Pudritz 1985). • Disk photo-evaporation could create a low-velocity disk outflow (e.g. Hollenbach et al. 1994; Yorke & Welz 1996). • Radiation pressure higher for dusty gas (e.g. Wolfire & Cassinelli 1987), may contribute to flow acceleration and a ...
RADIO OBSERVATIONS RELATED TO STAR FORMATION P. G.
... 3) A Possible Evolutionary Sequence of Ο and Β Stars and their Protostellar Shells The complexity of the subject warrants a reversal of the usual procedure; we introduce the review of observations (Sect. II) by outlining a working hypothesis for the evolutionary sequence of Ο and Β stars. This seque ...
... 3) A Possible Evolutionary Sequence of Ο and Β Stars and their Protostellar Shells The complexity of the subject warrants a reversal of the usual procedure; we introduce the review of observations (Sect. II) by outlining a working hypothesis for the evolutionary sequence of Ο and Β stars. This seque ...
hal.archives-ouvertes.fr - HAL-ENS
... the fixed spherical mirror. However, we may get direct spillover from the sky around the spherical primary reflector due to an incomplete apodisation inside the focal system. Continuum emission is perfectly removed in both modes, but line emission, if any, may remain when using the frequencyswitch m ...
... the fixed spherical mirror. However, we may get direct spillover from the sky around the spherical primary reflector due to an incomplete apodisation inside the focal system. Continuum emission is perfectly removed in both modes, but line emission, if any, may remain when using the frequencyswitch m ...
Modeling the Point Spread Function Using Principal
... function than can be created by a single image. Observational campaigns in the near future, such as LSST (www.lsst.org/lsst_home.shtml), will perform large surveys and take many images of each target, reducing the random noise in each image. Random noise scales as a factor of 1/ N , where N is the n ...
... function than can be created by a single image. Observational campaigns in the near future, such as LSST (www.lsst.org/lsst_home.shtml), will perform large surveys and take many images of each target, reducing the random noise in each image. Random noise scales as a factor of 1/ N , where N is the n ...
near-infrared adaptive optics imaging of high-redshift
... (slightly saturated) star at about 600 from the target and by a couple of faint stars in the field. The core of the PSF was thus defined by the two faint stars while the external wing was constrained by the bright one ( labeled PSF in Fig. 3). The PSF was then adjusted according to the distortion ma ...
... (slightly saturated) star at about 600 from the target and by a couple of faint stars in the field. The core of the PSF was thus defined by the two faint stars while the external wing was constrained by the bright one ( labeled PSF in Fig. 3). The PSF was then adjusted according to the distortion ma ...
Modeling the chemical evolution of the Galaxy halo
... unraveling the origin of halo stars through a detailed analysis of their chemical abundances revealed the existence of two distinct halo populations with a systematic difference in [α/Fe], [Cu/Fe], [Zn/Fe] and [Ba/Y], but not in [Mn/Fe], at a given metallicity (Nissen & Schuster 2010, 2011, and refer ...
... unraveling the origin of halo stars through a detailed analysis of their chemical abundances revealed the existence of two distinct halo populations with a systematic difference in [α/Fe], [Cu/Fe], [Zn/Fe] and [Ba/Y], but not in [Mn/Fe], at a given metallicity (Nissen & Schuster 2010, 2011, and refer ...
pps - TUM
... AGB stars and s-process Predominantly thought to occur in pulsating, low mass Asymptotic Giant Branch (AGB) stars, between 1.5 and 3 solar masses. These stars have largely exhausted core Heburning, and are instead burning He and H (not at the same time!) in their shells around the core. Protons mix ...
... AGB stars and s-process Predominantly thought to occur in pulsating, low mass Asymptotic Giant Branch (AGB) stars, between 1.5 and 3 solar masses. These stars have largely exhausted core Heburning, and are instead burning He and H (not at the same time!) in their shells around the core. Protons mix ...
Chemical Composition of Selected Metal Poor Stars
... by GalaCtic chemical evolution (chemical enrichment history of our galaxy). Theories of Big Bang nucleosynthesis suggest that, it was mainly hydrogen, helium and little amount of elements upto boron which were synthesized primordially. Other metals (elements heavier than lithium) were formed from th ...
... by GalaCtic chemical evolution (chemical enrichment history of our galaxy). Theories of Big Bang nucleosynthesis suggest that, it was mainly hydrogen, helium and little amount of elements upto boron which were synthesized primordially. Other metals (elements heavier than lithium) were formed from th ...
CoRoT pictures transiting exoplanets
... These discoveries triggered a new field of research and extreme enthusiasm in the astrophysical community. A third method is quickly proposed and experimented on the first detected radial-velocity planets: it consists in searching for a slight dimming of the star’s light that would be due to the cr ...
... These discoveries triggered a new field of research and extreme enthusiasm in the astrophysical community. A third method is quickly proposed and experimented on the first detected radial-velocity planets: it consists in searching for a slight dimming of the star’s light that would be due to the cr ...
Neutron stars: the densest state of condensed matter
... conference in Paris in 1939, Chandrasekhar also pointed out “If the degenerate core attain sufficiently high densities, the protons and electrons will combine to form neutrons. This would cause a sudden diminution of pressure resulting in the collapse of the star to a neutron core.” A neutron star s ...
... conference in Paris in 1939, Chandrasekhar also pointed out “If the degenerate core attain sufficiently high densities, the protons and electrons will combine to form neutrons. This would cause a sudden diminution of pressure resulting in the collapse of the star to a neutron core.” A neutron star s ...
The Blue Stragglers in M67 and Single
... population. 3.1. Fitting the Observed SEDs for Brightest Members For all the luminous high membership probability stragglers, among which 24 are classiÐed as blue stragglers (more luminous and bluer than the main-sequence turno† point) as listed in Table 1, we have 11 Ðlters covering 3890È9190 A th ...
... population. 3.1. Fitting the Observed SEDs for Brightest Members For all the luminous high membership probability stragglers, among which 24 are classiÐed as blue stragglers (more luminous and bluer than the main-sequence turno† point) as listed in Table 1, we have 11 Ðlters covering 3890È9190 A th ...
Orbital period decay of compact black hole X
... Aims. Observations have provided evidence that circumbinary disks around two compact black hole X-ray binaries may exist. Our analysis shows that, for some reasonable parameters, tidal torque between the circumbinary disk and the binary can efficiently extract the orbital angular momentum from the bin ...
... Aims. Observations have provided evidence that circumbinary disks around two compact black hole X-ray binaries may exist. Our analysis shows that, for some reasonable parameters, tidal torque between the circumbinary disk and the binary can efficiently extract the orbital angular momentum from the bin ...
205 Advances in Natural and Applied Sciences, 4(2): 205-209, 2010 ISSN 1995-0772
... multiple stellar systems. A sub-class of binary systems are X-ray binaries, the systems in which a compact object (a white dwarf, neutron star or a black hole formed after collapse of an ordinary star) and a stellar companion, orbit each other at a distance small enough to enable mass transfer from ...
... multiple stellar systems. A sub-class of binary systems are X-ray binaries, the systems in which a compact object (a white dwarf, neutron star or a black hole formed after collapse of an ordinary star) and a stellar companion, orbit each other at a distance small enough to enable mass transfer from ...
Lecture 2. Thermal evolution and surface emission of neutron stars
... Slow cooling for different EoS ...
... Slow cooling for different EoS ...
3. Solar System Formation and Early Evolution
... (i) The Sun was born in a ‘‘rich’’, Orion-like environment. (see Hillenbrand 1997; Figure 3.3) The most massive stars (the Trapezium-like stars) are very hot, and thus emit UV photons able to strongly ionize their immediate environment. The disks of the less massive stars then tend also to be ionize ...
... (i) The Sun was born in a ‘‘rich’’, Orion-like environment. (see Hillenbrand 1997; Figure 3.3) The most massive stars (the Trapezium-like stars) are very hot, and thus emit UV photons able to strongly ionize their immediate environment. The disks of the less massive stars then tend also to be ionize ...
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.