betelgeuse and the red supergiants
... Red supergiants are not supposed to rotate. This erroneous assumption has its origin in the fact that they cannot have evolved from (much smaller) stars rotating faster than break-up speed. Hence one would not expect red supergiants to rotate much faster than several kilometres per second (at the eq ...
... Red supergiants are not supposed to rotate. This erroneous assumption has its origin in the fact that they cannot have evolved from (much smaller) stars rotating faster than break-up speed. Hence one would not expect red supergiants to rotate much faster than several kilometres per second (at the eq ...
Shock interactions, turbulence and the origin of the stellar mass
... ISM of the Galaxy is seen in the neutral hydrogen (H I) gas observations such as the Canadian Galactic Plane Survey [14]. These 21 cm maps of radio emission show that the diffuse ISM is highly filamentary, and abounds in bubbles, cavities and channels carved out by radiation, winds and supernova exp ...
... ISM of the Galaxy is seen in the neutral hydrogen (H I) gas observations such as the Canadian Galactic Plane Survey [14]. These 21 cm maps of radio emission show that the diffuse ISM is highly filamentary, and abounds in bubbles, cavities and channels carved out by radiation, winds and supernova exp ...
ON THE ORIGIN OF THE SALPETER SLOPE FOR THE INITIAL
... we are interested only in the upper IMF, however, scale-free cloud fragmentation plausibly dominates in this regime. But we note that our model contrasts with those in which the IMF slope results from physics that causes fragmentation into a steeper core mass distribution (e.g., Padoan & Nordlund 20 ...
... we are interested only in the upper IMF, however, scale-free cloud fragmentation plausibly dominates in this regime. But we note that our model contrasts with those in which the IMF slope results from physics that causes fragmentation into a steeper core mass distribution (e.g., Padoan & Nordlund 20 ...
O stars with weak winds: the Galactic case - Max-Planck
... situations, we checked that the Hα line given by our models with Ṁ estimated from UV was consistent with the observed line. We want to stress here that it is only because metals are now included in a reliable way in new generation atmosphere models that such a study is possible. Indeed, UV metallic ...
... situations, we checked that the Hα line given by our models with Ṁ estimated from UV was consistent with the observed line. We want to stress here that it is only because metals are now included in a reliable way in new generation atmosphere models that such a study is possible. Indeed, UV metallic ...
The formation of carbon dioxide in molecular
... surfaces investigated. Experiments using O3 as a substrate generated more CO2 than those using O2 , as can be clearly seen by comparing the dot-dashed lines (O3 ) with the dashed lines (O2 ) in Figure 2. It is important to note that the yields of ...
... surfaces investigated. Experiments using O3 as a substrate generated more CO2 than those using O2 , as can be clearly seen by comparing the dot-dashed lines (O3 ) with the dashed lines (O2 ) in Figure 2. It is important to note that the yields of ...
Astronomy Astrophysics Kuiper belts around nearby stars &
... An additional advantage in making observations in the submm region is that measured integrated fluxes are directly proportional to the temperature and mass of the disk, due to the fact that they (in most cases) sample the Rayleigh-Jeans tail of the spectral energy distribution (SED), and that the di ...
... An additional advantage in making observations in the submm region is that measured integrated fluxes are directly proportional to the temperature and mass of the disk, due to the fact that they (in most cases) sample the Rayleigh-Jeans tail of the spectral energy distribution (SED), and that the di ...
Stellar Oscillations Lecture Notes on Jørgen Christensen-Dalsgaard
... of the mean density of the star, two periods roughly speaking allow determination of its mass and radius. It is striking that, as discussed by Petersen, even this limited information about the stars led to a conflict with the results of stellar evolution theory which has only been resolved very rece ...
... of the mean density of the star, two periods roughly speaking allow determination of its mass and radius. It is striking that, as discussed by Petersen, even this limited information about the stars led to a conflict with the results of stellar evolution theory which has only been resolved very rece ...
THE ORIGIN AND EVOLUTION OF PLANETARY NEBULAE
... certain atoms with metastable states, which do not have the time to emit radiation because of collisional deexcitation in the high-density terrestrial environment, will radiate under interstellar conditions. Bowen, in 1928, identified eight of the strongest nebular lines as being due to metastable s ...
... certain atoms with metastable states, which do not have the time to emit radiation because of collisional deexcitation in the high-density terrestrial environment, will radiate under interstellar conditions. Bowen, in 1928, identified eight of the strongest nebular lines as being due to metastable s ...
Gas lines from the 5-Myr old optically thin disk around HD141569A
... Context. The gas- and dust dissipation processes in disks around young stars remain uncertain despite numerous studies. At the distance of ∼ 99–116 pc, HD141569A is one of the nearest HerbigAe stars that is surrounded by a tenuous disk, probably in transition between a massive primordial disk and a ...
... Context. The gas- and dust dissipation processes in disks around young stars remain uncertain despite numerous studies. At the distance of ∼ 99–116 pc, HD141569A is one of the nearest HerbigAe stars that is surrounded by a tenuous disk, probably in transition between a massive primordial disk and a ...
Scaling behavior in Rayleigh-Bénard convection
... control parameters are usually taken to be Ra, E, and P r, which are defined in table 1. The buoyancy forcing is characterized by the Rayleigh number, Ra. The period of rotation is characterized by the Ekman number, E. The Prandtl number, P r, characterizes the fluid itself as a ratio of viscous to ...
... control parameters are usually taken to be Ra, E, and P r, which are defined in table 1. The buoyancy forcing is characterized by the Rayleigh number, Ra. The period of rotation is characterized by the Ekman number, E. The Prandtl number, P r, characterizes the fluid itself as a ratio of viscous to ...
Magnetars: properties, origin and evolution
... its spectrum is well fit by the two-blackbody model while the power-law plus blackbody is rejected with high confidence (Tiengo et al. 2008). On the other hand, a power-law component is certainly present in the hard X-ray range. Several magnetars have been detected up to ∼150 keV with large pulsed f ...
... its spectrum is well fit by the two-blackbody model while the power-law plus blackbody is rejected with high confidence (Tiengo et al. 2008). On the other hand, a power-law component is certainly present in the hard X-ray range. Several magnetars have been detected up to ∼150 keV with large pulsed f ...
The CN/C15 N isotopic ratio towards dark clouds
... and C15 N lines towards L1498, which could not be ascribed to any obvious technical issue. We note, however, that the uncertainty on the rest frequency reported in the Cologne Database for Molecular Spectroscopy (Müller et al. 2005) is 0.1 MHz, or 0.25 km s−1 , which could account for the observed ...
... and C15 N lines towards L1498, which could not be ascribed to any obvious technical issue. We note, however, that the uncertainty on the rest frequency reported in the Cologne Database for Molecular Spectroscopy (Müller et al. 2005) is 0.1 MHz, or 0.25 km s−1 , which could account for the observed ...
The dual nature of the Milky Way stellar halo
... be stripped from accreted DM satellites, hosting dwarf galaxies, during their orbits before the final merger. Minor mergers are the most probable sources for these kind of stars, firstly because they do not destroy the galactic disk and can thus happen in all evolutionary phases of the life of a disk ...
... be stripped from accreted DM satellites, hosting dwarf galaxies, during their orbits before the final merger. Minor mergers are the most probable sources for these kind of stars, firstly because they do not destroy the galactic disk and can thus happen in all evolutionary phases of the life of a disk ...
Constraining the Contribution of Galaxies and Active Galactic Nuclei
... among the simulation results. Thus, there is as yet no consensus on the value of the escape fraction, and this fact leads to the significant uncertainty of the contribution of high-z galaxies to cosmic reionization. Active galactic nuclei (AGNs) are also expected to have been another type of ionizin ...
... among the simulation results. Thus, there is as yet no consensus on the value of the escape fraction, and this fact leads to the significant uncertainty of the contribution of high-z galaxies to cosmic reionization. Active galactic nuclei (AGNs) are also expected to have been another type of ionizin ...
THE CHEMICAL COMPOSITION AND AGE OF THE METAL
... We have combined new high-resolution spectra obtained with the Hubble Space Telescope (HST) and ground-based facilities to make a comprehensive new abundance analysis of the metal-poor, halo star BD +17 3248. We have detected the third r-process peak elements osmium, platinum, and (for the first tim ...
... We have combined new high-resolution spectra obtained with the Hubble Space Telescope (HST) and ground-based facilities to make a comprehensive new abundance analysis of the metal-poor, halo star BD +17 3248. We have detected the third r-process peak elements osmium, platinum, and (for the first tim ...
and galaxies
... together to make ‘grains’. When this region heats up again, the increased radiation pressure from the star pushes these out of the star’s atmosphere and into space. 2GLSS P.H. Regan ...
... together to make ‘grains’. When this region heats up again, the increased radiation pressure from the star pushes these out of the star’s atmosphere and into space. 2GLSS P.H. Regan ...
Giant planet and brown dwarf formation
... these two populations has no physical justification and brings scientific confusion. In contrast, brown dwarfs and giant planets might bear some imprints of their formation mechanism, notably in their mean density and in the physical properties of their atmosphere. Future direct imaging surveys will ...
... these two populations has no physical justification and brings scientific confusion. In contrast, brown dwarfs and giant planets might bear some imprints of their formation mechanism, notably in their mean density and in the physical properties of their atmosphere. Future direct imaging surveys will ...
the formation of giant molecular clouds
... of the carbon monoxide molecule. This is because circumstances conspire to make 12 CO easy to observe and other species (including molecular hydrogen) difficult to observe, both in practice and in principle. Since we are forced to view the molecular galaxy through this narrow window, the physics of ...
... of the carbon monoxide molecule. This is because circumstances conspire to make 12 CO easy to observe and other species (including molecular hydrogen) difficult to observe, both in practice and in principle. Since we are forced to view the molecular galaxy through this narrow window, the physics of ...
