Supernovae: An example of complexity in the physics of
... regime we assume that an adiabatic approximation is possible, neglecting the diffusion and/or mechanical arrangement processes which could be responsible of some discontinuities in the route to equilibrium, because these processes have a short time scale compared to the slow evolution time. While the ...
... regime we assume that an adiabatic approximation is possible, neglecting the diffusion and/or mechanical arrangement processes which could be responsible of some discontinuities in the route to equilibrium, because these processes have a short time scale compared to the slow evolution time. While the ...
3 science case - Giant Magellan Telescope Organization
... quality probes of the physical properties of gas giant planets. Nearby field stars, stellar associations, and star-forming regions provide good targets for direct detection of terrestrial and gas giant planets. At distances of 50-100 pc, the TW Hya (10 Myr), η Cha (10 Myr) and Tuc-Hor (30 Myr) assoc ...
... quality probes of the physical properties of gas giant planets. Nearby field stars, stellar associations, and star-forming regions provide good targets for direct detection of terrestrial and gas giant planets. At distances of 50-100 pc, the TW Hya (10 Myr), η Cha (10 Myr) and Tuc-Hor (30 Myr) assoc ...
L. Zampieri - Astrophysics Group of the University of Crete
... role in forming and/or triggering the ULX phenomenon: How to explain this connection? Try to explan it within the framework of BH formation from the direct collapse of massive stars in low-metallicity environments: If a massive star retains an envelope more massive than ~30-40 Msun at the time of ex ...
... role in forming and/or triggering the ULX phenomenon: How to explain this connection? Try to explan it within the framework of BH formation from the direct collapse of massive stars in low-metallicity environments: If a massive star retains an envelope more massive than ~30-40 Msun at the time of ex ...
Standardized Test Prep Chapter 30 Multiple Choice, continued
... • A protostar’s temperature continually increases until it reaches about 10,000,000°C. • At this temperature, nuclear fusion begins. Nuclear fusion is a process in which less-massive atomic nuclei combine to form more-massive nuclei. The process releases enormous amounts of energy. • The onset of nu ...
... • A protostar’s temperature continually increases until it reaches about 10,000,000°C. • At this temperature, nuclear fusion begins. Nuclear fusion is a process in which less-massive atomic nuclei combine to form more-massive nuclei. The process releases enormous amounts of energy. • The onset of nu ...
Chapter 30 - Todd County Schools
... • A protostar’s temperature continually increases until it reaches about 10,000,000°C. • At this temperature, nuclear fusion begins. Nuclear fusion is a process in which less-massive atomic nuclei combine to form more-massive nuclei. The process releases enormous amounts of energy. • The onset of nu ...
... • A protostar’s temperature continually increases until it reaches about 10,000,000°C. • At this temperature, nuclear fusion begins. Nuclear fusion is a process in which less-massive atomic nuclei combine to form more-massive nuclei. The process releases enormous amounts of energy. • The onset of nu ...
The low-mass dispersed population around the Lupus clouds
... clearly shows the statistical signature of many previously unrecognized cold members of the Lupus 3 cloud, in addition to the numerous members already known from previous studies. The new members are mainly located in a distributed population, projected at large angular distances from the main dark ...
... clearly shows the statistical signature of many previously unrecognized cold members of the Lupus 3 cloud, in addition to the numerous members already known from previous studies. The new members are mainly located in a distributed population, projected at large angular distances from the main dark ...
Multiplicity in Early Stellar Evolution
... of 1 M⊙ , and a turbulent, high Mach number (13.7) velocity field. This simulation involved a sufficiently large population of stars and brown dwarfs (1250) so as to provide an excellent basis for comparison with observed multiple systems. It is remarkable that this simulation – which clearly omits ...
... of 1 M⊙ , and a turbulent, high Mach number (13.7) velocity field. This simulation involved a sufficiently large population of stars and brown dwarfs (1250) so as to provide an excellent basis for comparison with observed multiple systems. It is remarkable that this simulation – which clearly omits ...
WSokolov-PROTVINO
... the most distant explosions of massive stars at the end of their evolution. This is confirmed by observations of the "long" bursts, but, most probably, the "short" GRBs are also related to some very old compact objects formed in the course of evolution of the same massive stars. What is the red shif ...
... the most distant explosions of massive stars at the end of their evolution. This is confirmed by observations of the "long" bursts, but, most probably, the "short" GRBs are also related to some very old compact objects formed in the course of evolution of the same massive stars. What is the red shif ...
Galaxy Evolution Encyclopedia of Astronomy & Astrophysics eaa.iop.org Mauro Giavalisco
... times brighter than stars like the Sun, their total luminosity will approximately equal that of 2 × 1010 of these. Thus, during the star formation activity the galaxy increases its luminosity by ∼ 20%. Its colors also become bluer, because the radiation emitted by massive stars is very rich of light ...
... times brighter than stars like the Sun, their total luminosity will approximately equal that of 2 × 1010 of these. Thus, during the star formation activity the galaxy increases its luminosity by ∼ 20%. Its colors also become bluer, because the radiation emitted by massive stars is very rich of light ...
SUPERNOVA REMNANT SHOCKS IN AN INHOMOGENEOUS
... but it would first be necessary to determine which SNRs are interacting with the "pristine" ISM, unaffected by the progenitor star. As we shall see below, this is not a straightforward task. Energy injection via stellar winds is negligible for low mass stars. For massive stars, the total wind energy ...
... but it would first be necessary to determine which SNRs are interacting with the "pristine" ISM, unaffected by the progenitor star. As we shall see below, this is not a straightforward task. Energy injection via stellar winds is negligible for low mass stars. For massive stars, the total wind energy ...
Galaxy Evolution
... times brighter than stars like the Sun, their total luminosity will approximately equal that of 2 × 1010 of these. Thus, during the star formation activity the galaxy increases its luminosity by ∼ 20%. Its colors also become bluer, because the radiation emitted by massive stars is very rich of light ...
... times brighter than stars like the Sun, their total luminosity will approximately equal that of 2 × 1010 of these. Thus, during the star formation activity the galaxy increases its luminosity by ∼ 20%. Its colors also become bluer, because the radiation emitted by massive stars is very rich of light ...
The Space Density of Spiral Galaxies as f(magnitude, size and
... observed trends between stellar ages & metallicities and galaxy surface brightness parameters ...
... observed trends between stellar ages & metallicities and galaxy surface brightness parameters ...
chemical abundances for a-and f-type supergiant stars
... phase, the A–F supergiants are able to resume thermal and radiative equilibrium through convection in the outer layers and shows an altered CNO abundance due to the first dredge-up (1DUP) event. On the other hand, less massive A–F supergiants (M < 10 M⊙ ) have also initiated the He-core burning with ...
... phase, the A–F supergiants are able to resume thermal and radiative equilibrium through convection in the outer layers and shows an altered CNO abundance due to the first dredge-up (1DUP) event. On the other hand, less massive A–F supergiants (M < 10 M⊙ ) have also initiated the He-core burning with ...
KIC 8462852 Faded Throughout the Kepler Mission
... first is a long-term dimming at a linear rate from the beginning of the Kepler mission until approximately Quarter 13. The dimming then increases rapidly such that the observed flux from the star decreases by approximately 2.5% over 200 days. For the final 200 days of the Kepler mission, the light c ...
... first is a long-term dimming at a linear rate from the beginning of the Kepler mission until approximately Quarter 13. The dimming then increases rapidly such that the observed flux from the star decreases by approximately 2.5% over 200 days. For the final 200 days of the Kepler mission, the light c ...
The destruction and survival of polycyclic aromatic hydrocarbons in
... The observed emission can be explained in models of an irradiated disk (Habart et al. 2004; Visser et al. 2007; Dullemond et al. 2007a). The infrared space observatory (ISO) looked at a few of the much fainter T Tauri stars, but without a clear PAH detection (Siebenmorgen et al. 2000). In the Evans ...
... The observed emission can be explained in models of an irradiated disk (Habart et al. 2004; Visser et al. 2007; Dullemond et al. 2007a). The infrared space observatory (ISO) looked at a few of the much fainter T Tauri stars, but without a clear PAH detection (Siebenmorgen et al. 2000). In the Evans ...
New Evidence for Mass-Loss from δ Cephei from H i 21
... pattern in the VLA images caused by large-scale Galactic emission diminishes near VLSR = 13.8 km s−1 . Furthermore, that same channel exhibits an extended H i emission region centered near the position of δ Cephei. Looking toward higher velocities, we find a series of 15 contiguous channels where spa ...
... pattern in the VLA images caused by large-scale Galactic emission diminishes near VLSR = 13.8 km s−1 . Furthermore, that same channel exhibits an extended H i emission region centered near the position of δ Cephei. Looking toward higher velocities, we find a series of 15 contiguous channels where spa ...
Giant Planet Formation, Evolution, and Internal Structure
... Z-component of the planetary envelope can be stellar, substellar, or super-stellar. If all the planetesimals reach the core without depositing mass in the envelope, the planetary envelope is likely to have a composition similar to the gas in the protoplanetary disk. However, enrichment of a gas gian ...
... Z-component of the planetary envelope can be stellar, substellar, or super-stellar. If all the planetesimals reach the core without depositing mass in the envelope, the planetary envelope is likely to have a composition similar to the gas in the protoplanetary disk. However, enrichment of a gas gian ...
Stellar evolution
Stellar evolution is the process by which a star changes during its lifetime. Depending on the mass of the star, this lifetime ranges from a few million years for the most massive to trillions of years for the least massive, which is considerably longer than the age of the universe. The table shows the lifetimes of stars as a function of their masses. All stars are born from collapsing clouds of gas and dust, often called nebulae or molecular clouds. Over the course of millions of years, these protostars settle down into a state of equilibrium, becoming what is known as a main-sequence star.Nuclear fusion powers a star for most of its life. Initially the energy is generated by the fusion of hydrogen atoms at the core of the main-sequence star. Later, as the preponderance of atoms at the core becomes helium, stars like the Sun begin to fuse hydrogen along a spherical shell surrounding the core. This process causes the star to gradually grow in size, passing through the subgiant stage until it reaches the red giant phase. Stars with at least half the mass of the Sun can also begin to generate energy through the fusion of helium at their core, whereas more-massive stars can fuse heavier elements along a series of concentric shells. Once a star like the Sun has exhausted its nuclear fuel, its core collapses into a dense white dwarf and the outer layers are expelled as a planetary nebula. Stars with around ten or more times the mass of the Sun can explode in a supernova as their inert iron cores collapse into an extremely dense neutron star or black hole. Although the universe is not old enough for any of the smallest red dwarfs to have reached the end of their lives, stellar models suggest they will slowly become brighter and hotter before running out of hydrogen fuel and becoming low-mass white dwarfs.Stellar evolution is not studied by observing the life of a single star, as most stellar changes occur too slowly to be detected, even over many centuries. Instead, astrophysicists come to understand how stars evolve by observing numerous stars at various points in their lifetime, and by simulating stellar structure using computer models.In June 2015, astronomers reported evidence for Population III stars in the Cosmos Redshift 7 galaxy at z = 6.60. Such stars are likely to have existed in the very early universe (i.e., at high redshift), and may have started the production of chemical elements heavier than hydrogen that are needed for the later formation of planets and life as we know it.