Stellar Dynamics
... medium) flows into the centre of the cluster, falling into the gravitational potential well. As a result this gas gets heated up and emits copious amount of X-rays through which it can be observed. Near the centre of rich clusters the gas becomes dense and its cooling time is estimated to be shorter ...
... medium) flows into the centre of the cluster, falling into the gravitational potential well. As a result this gas gets heated up and emits copious amount of X-rays through which it can be observed. Near the centre of rich clusters the gas becomes dense and its cooling time is estimated to be shorter ...
Asteroseismology and stellar rotation - IAG-Usp
... --> Observed from ground with Harps(Mosser et al 2005): detection of solar like oscillation Differences between input splitting values from simulation (Roxburgh, Barban) and output splitting values from blind analysis (Appourchaux) ...
... --> Observed from ground with Harps(Mosser et al 2005): detection of solar like oscillation Differences between input splitting values from simulation (Roxburgh, Barban) and output splitting values from blind analysis (Appourchaux) ...
Formation and composition of planets around very low mass stars
... the planetary mass: planets that do not contain a lot of water are generally of lower mass (below ∼ 1M⊕ , although some can be as massive as ∼ 1.5M⊕ ), and planets totally devoid of water are all less massive than 1M⊕ , and even lower than 0.4M⊕ if one does not consider the massive disks. This can b ...
... the planetary mass: planets that do not contain a lot of water are generally of lower mass (below ∼ 1M⊕ , although some can be as massive as ∼ 1.5M⊕ ), and planets totally devoid of water are all less massive than 1M⊕ , and even lower than 0.4M⊕ if one does not consider the massive disks. This can b ...
Evolution of Neutron Star Magnetic Fields
... from ∼ 108 to 1013 G, as inferred from radio pulsars, accreting X-ray pulsars and lowmass X-ray binaries. There also exists another class of objects, consisting of anomalous X-ray pulsars and soft gamma repeaters, often referred to under the umbrella term “magnetars”, in which the magnetic field of ...
... from ∼ 108 to 1013 G, as inferred from radio pulsars, accreting X-ray pulsars and lowmass X-ray binaries. There also exists another class of objects, consisting of anomalous X-ray pulsars and soft gamma repeaters, often referred to under the umbrella term “magnetars”, in which the magnetic field of ...
Period Changes of Delta Scuti Stars and Stellar Evolution
... For the radial pulsators of Pop. I, the observations indicate (1/P) dP/dt values around 10−7 year−1 with equal distribution between period increases and decreases. The evolutionary models, on the other hand, predict that the vast majority should show increasing periods. This increase should be a fac ...
... For the radial pulsators of Pop. I, the observations indicate (1/P) dP/dt values around 10−7 year−1 with equal distribution between period increases and decreases. The evolutionary models, on the other hand, predict that the vast majority should show increasing periods. This increase should be a fac ...
- Cosmotography
... dwarfs have been identified observationally (Stinson et al. 2009), but it is not clear if these stars were accreted, or formed in-situ. Star formation in dwarfs is thought to occur in stochastic episodes (Tolstoy et al. 2009; Weisz et al. 2011), which could be triggered by accretion events. An iconi ...
... dwarfs have been identified observationally (Stinson et al. 2009), but it is not clear if these stars were accreted, or formed in-situ. Star formation in dwarfs is thought to occur in stochastic episodes (Tolstoy et al. 2009; Weisz et al. 2011), which could be triggered by accretion events. An iconi ...
Star Magnitude - ScienceEducationatNewPaltz
... The First Magnitude Stars Table lists the brightest stars in the sky that are -1, 0 and 1 magnitude. Sirius is the brightest at -1.44 magnitude. These stars are referred to as First Magnitude stars since they are all 1 magnitude or brighter. Brightness of stars is assigned a number starting with the ...
... The First Magnitude Stars Table lists the brightest stars in the sky that are -1, 0 and 1 magnitude. Sirius is the brightest at -1.44 magnitude. These stars are referred to as First Magnitude stars since they are all 1 magnitude or brighter. Brightness of stars is assigned a number starting with the ...
fundamental properties of kepler planet- candidate
... (Vandakurov 1968; Tassoul 1980; Gough 1986). The large frequency separation Δν is the spacing between modes with the same spherical degree l and consecutive radial order n, and probes the sound travel time across the stellar diameter. This means that Δν is related to the mean stellar density and is ...
... (Vandakurov 1968; Tassoul 1980; Gough 1986). The large frequency separation Δν is the spacing between modes with the same spherical degree l and consecutive radial order n, and probes the sound travel time across the stellar diameter. This means that Δν is related to the mean stellar density and is ...
here
... The path to the Galactic Centre • ~8kpc path from the Earth to the Galactic Centre • mostly through diffuse interstellar material, but with some molecular components near the centre. • Evidence for a slow increase in heavy element abundance towards the GC The Galactic Centre 30 magnitudes of visu ...
... The path to the Galactic Centre • ~8kpc path from the Earth to the Galactic Centre • mostly through diffuse interstellar material, but with some molecular components near the centre. • Evidence for a slow increase in heavy element abundance towards the GC The Galactic Centre 30 magnitudes of visu ...
The Search for Exoplanets - Worcester Polytechnic Institute
... other stellar systems, not all stars are made equally, nor are the nebulae from which they are formed made of the same materials. Therefore, when we observe all of the bodies that inhabit our Solar System, we are looking only at a single microcosm in the vast expanse of the greater cosmos. Naturally ...
... other stellar systems, not all stars are made equally, nor are the nebulae from which they are formed made of the same materials. Therefore, when we observe all of the bodies that inhabit our Solar System, we are looking only at a single microcosm in the vast expanse of the greater cosmos. Naturally ...
Devil physics The baddest class on campus IB Physics
... (energy) required to completely separate the nucleons of a nucleus The work required to remove one nucleon from the nucleus is very roughly the binding energy divided by the number of nucleons More importantly, the binding energy of a nucleus is a measure of how stable it is – higher the binding ...
... (energy) required to completely separate the nucleons of a nucleus The work required to remove one nucleon from the nucleus is very roughly the binding energy divided by the number of nucleons More importantly, the binding energy of a nucleus is a measure of how stable it is – higher the binding ...
Core Formation in Giant Gaseous Protoplanets
... immediately in objects of 5 MJ or larger, and instead of contributing to core formation, the grains evaporate in the planetary envelope enriching it with refractory material. Protoplanets with smaller masses are cold enough to let the grains survive. We follow the silicate grains as they grow and se ...
... immediately in objects of 5 MJ or larger, and instead of contributing to core formation, the grains evaporate in the planetary envelope enriching it with refractory material. Protoplanets with smaller masses are cold enough to let the grains survive. We follow the silicate grains as they grow and se ...
PDF only - at www.arxiv.org.
... have to be corrected for the environment of Hot Jupiters, where the UV radiation field is many orders of magnitude higher. In order to estimate the correction factor for the mass loss of HD 209458 b and other Hot Jupiters of interest, we modeled the radiation field of the stars, considering them as ...
... have to be corrected for the environment of Hot Jupiters, where the UV radiation field is many orders of magnitude higher. In order to estimate the correction factor for the mass loss of HD 209458 b and other Hot Jupiters of interest, we modeled the radiation field of the stars, considering them as ...
Nucleosynthesis of heavy elements in gamma ray bursts
... material glows with X-rays no matter what, while the Xrays detected by Chandra and other telescopes are generated only after heating with shock waves from the explosion. Because the non-radioactive material only lights up after the explosion, it does not offer a direct look at the blast itself. ...
... material glows with X-rays no matter what, while the Xrays detected by Chandra and other telescopes are generated only after heating with shock waves from the explosion. Because the non-radioactive material only lights up after the explosion, it does not offer a direct look at the blast itself. ...
The chemical case for no winds in dwarf irregular galaxies
... of these objects is the presence of strong galactic winds. If they have a low mass and a high star formation rate (SFR), the energy injected by supernova (SN) explosions may be able to eject some fraction of their gas into the intergalactic medium (Dekel & Silk 1986). The existence of such an outflo ...
... of these objects is the presence of strong galactic winds. If they have a low mass and a high star formation rate (SFR), the energy injected by supernova (SN) explosions may be able to eject some fraction of their gas into the intergalactic medium (Dekel & Silk 1986). The existence of such an outflo ...
Presentation
... nor-LMA-s and inv-LMA-s are degenerate, but inv-LMA-L is clearly discriminated from nor-LMA-L. If the mixing parameter 13 is -L, mass hierarchy problem is solved. ...
... nor-LMA-s and inv-LMA-s are degenerate, but inv-LMA-L is clearly discriminated from nor-LMA-L. If the mixing parameter 13 is -L, mass hierarchy problem is solved. ...
Chapter 15 Stars, Galaxies, and Universe
... lot of energy •When star uses up hydrogen helium can start fusing and creating new elements •Helium fuses in core to become carbon, oxygen •Massive stars produce heavier elements like iron •Stars without fuel become white dwarf, neutron star or black hole •Low mass star red giant planetary nebula wh ...
... lot of energy •When star uses up hydrogen helium can start fusing and creating new elements •Helium fuses in core to become carbon, oxygen •Massive stars produce heavier elements like iron •Stars without fuel become white dwarf, neutron star or black hole •Low mass star red giant planetary nebula wh ...
Name - MIT
... B) why have we not observed alien civilizations even though simple arguments would suggest that some of these civilizations ought to have spread throughout the galaxy by now? C) why hasn’t life evolved on Mars if it has evolved on Earth? D) why does a spiral galaxy's rotation speed depend on its mas ...
... B) why have we not observed alien civilizations even though simple arguments would suggest that some of these civilizations ought to have spread throughout the galaxy by now? C) why hasn’t life evolved on Mars if it has evolved on Earth? D) why does a spiral galaxy's rotation speed depend on its mas ...
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.