![Constellations, Looking Far Away, and Stars/Stellar Evolution](http://s1.studyres.com/store/data/014287793_1-3c24f4c58aeadb33254d5f2d9979dd3d-300x300.png)
Constellations, Looking Far Away, and Stars/Stellar Evolution
... Read aloud. The graph of how the temperatures and luminosities of stars are related is known as the Hertzsprung-Russell or H-R diagram. From this graph, we can also get an estimate of the size of a star, its radius. Astronomers worked with this graph long before they knew why stars varied in this wa ...
... Read aloud. The graph of how the temperatures and luminosities of stars are related is known as the Hertzsprung-Russell or H-R diagram. From this graph, we can also get an estimate of the size of a star, its radius. Astronomers worked with this graph long before they knew why stars varied in this wa ...
Second Semester Study Guide
... 26. Why was the recent discovery that planets more massive than Jupiter orbit nearby stars in small orbits surprising? A. Because according to the nebular hypothesis, massive planets should only form away from their star. B. The density of these planets is very high. C. According to the nebular hyp ...
... 26. Why was the recent discovery that planets more massive than Jupiter orbit nearby stars in small orbits surprising? A. Because according to the nebular hypothesis, massive planets should only form away from their star. B. The density of these planets is very high. C. According to the nebular hyp ...
Chapter 8 Formation of Stars
... • The bipolar outflows could in principle be explained by an accretion disk around the young T-Tauri stars that would form as a result of conservation of angular momentum for the infalling matter. • Then, if there are strong winds emanating from the star, they would tend to be directed in bipolar fl ...
... • The bipolar outflows could in principle be explained by an accretion disk around the young T-Tauri stars that would form as a result of conservation of angular momentum for the infalling matter. • Then, if there are strong winds emanating from the star, they would tend to be directed in bipolar fl ...
Chapter 7 Formation of Stars
... • The bipolar outflows could in principle be explained by an accretion disk around the young T-Tauri stars that would form as a result of conservation of angular momentum for the infalling matter. • Then, if there are strong winds emanating from the star, they would tend to be directed in bipolar fl ...
... • The bipolar outflows could in principle be explained by an accretion disk around the young T-Tauri stars that would form as a result of conservation of angular momentum for the infalling matter. • Then, if there are strong winds emanating from the star, they would tend to be directed in bipolar fl ...
lect3 — 1 Measuring stars: What can be measured?
... stars tend to be somewhat variable, and their color doesn’t translate into luminosity quite so tightly as for something like the Sun. Cepheids: Classically, this is the most reliable stellar standard candle. This type of giant star is seen to have regular pulsations, and the pulsation period turns o ...
... stars tend to be somewhat variable, and their color doesn’t translate into luminosity quite so tightly as for something like the Sun. Cepheids: Classically, this is the most reliable stellar standard candle. This type of giant star is seen to have regular pulsations, and the pulsation period turns o ...
Classifying Spectra PDF version - the Home Page for Voyager2
... The spectral classes are specified by the letters O, B, A, F, G, K, M, L, T going hotter to colder. Each letter is subdivided by assigning a number 0 through 9 following the letter and going from hotter to colder. So B0 is colder than O9 and hotter than B1. Obviously not every type is shown. Origina ...
... The spectral classes are specified by the letters O, B, A, F, G, K, M, L, T going hotter to colder. Each letter is subdivided by assigning a number 0 through 9 following the letter and going from hotter to colder. So B0 is colder than O9 and hotter than B1. Obviously not every type is shown. Origina ...
Part I - User Web Areas at the University of York
... 1000 tonnes of heavy water in a 12 metre diameter transparent acrylic sphere viewed by approximately 9,600 PMTs 2 km underground in Ontario, Canada. Detection rate is about one neutrino per hour. Turned on in 1999 and was turned off on in 2006 although analysis of the data recorded still continues. ...
... 1000 tonnes of heavy water in a 12 metre diameter transparent acrylic sphere viewed by approximately 9,600 PMTs 2 km underground in Ontario, Canada. Detection rate is about one neutrino per hour. Turned on in 1999 and was turned off on in 2006 although analysis of the data recorded still continues. ...
Solutions for homework #5, AST 203, Spring 2009
... e. (15 points) A muon is a particle very much like an electron, only with more mass. Unlike electrons, muons are unstable; they have a half-life of only 2.2 × 10−6 seconds, after which they decay into an electron, a muon neutrino, and an anti-electron neutrino. Very fast-moving muons are produced in ...
... e. (15 points) A muon is a particle very much like an electron, only with more mass. Unlike electrons, muons are unstable; they have a half-life of only 2.2 × 10−6 seconds, after which they decay into an electron, a muon neutrino, and an anti-electron neutrino. Very fast-moving muons are produced in ...
The double-degenerate, super-Chandrasekhar nucleus of the
... system seems to have first undergone a phase of mass transfer via wind or stable Roche lobe overflow (RLOF), and then a CE. This is likely, as in order to have two oversized pre-WD stars with R=0.68-0.7 R⊙ still hot, the two events must have happened fast and consecutively. In addition, for the syst ...
... system seems to have first undergone a phase of mass transfer via wind or stable Roche lobe overflow (RLOF), and then a CE. This is likely, as in order to have two oversized pre-WD stars with R=0.68-0.7 R⊙ still hot, the two events must have happened fast and consecutively. In addition, for the syst ...
galaxies and stars
... They contain only one star but hundreds of planets. They may contain a few hundred stars in a space slightly larger than the solar system. They may contain billions of stars in a space much larger than our solar system. ...
... They contain only one star but hundreds of planets. They may contain a few hundred stars in a space slightly larger than the solar system. They may contain billions of stars in a space much larger than our solar system. ...
determining stellar parameters from star`s
... Planck's law. The stars do not radiate as black or even gray bodies. There are two reasons for these deviations. One is that temperature increases with depth in stars, so radiation from deeper layers corresponds to higher temperatures. The other is that the material in the star's atmosphere is not g ...
... Planck's law. The stars do not radiate as black or even gray bodies. There are two reasons for these deviations. One is that temperature increases with depth in stars, so radiation from deeper layers corresponds to higher temperatures. The other is that the material in the star's atmosphere is not g ...
mass loss of massive stars - of /proceedings
... the mass loss rate by a factor of ten only in the (short) red supergiant phase can affect the end point of stellar evolution: a star may become a supernova either as a red or as a blue supergiant depending on the mass loss history in the red supergiant phase. The material ejected just before the exp ...
... the mass loss rate by a factor of ten only in the (short) red supergiant phase can affect the end point of stellar evolution: a star may become a supernova either as a red or as a blue supergiant depending on the mass loss history in the red supergiant phase. The material ejected just before the exp ...
MS Word version
... This is a good time to emphasize that the light curve is showing normalized flux and that as we change the radius of a star we are changing the value of the total flux. If you now decrease the radius of star 1 the eclipses will get deeper until the two stars have the same radius (Example 1) and then ...
... This is a good time to emphasize that the light curve is showing normalized flux and that as we change the radius of a star we are changing the value of the total flux. If you now decrease the radius of star 1 the eclipses will get deeper until the two stars have the same radius (Example 1) and then ...
D ASTROPHYSICS
... Stars gas and radiation pressure Like the Sun, all stars initially form when gravity causes the gas in a gravity nebula to condense. As the atoms move towards one another, they lose gravitational potential energy that is converted into kinetic energy. This raises the temperature of the atoms which t ...
... Stars gas and radiation pressure Like the Sun, all stars initially form when gravity causes the gas in a gravity nebula to condense. As the atoms move towards one another, they lose gravitational potential energy that is converted into kinetic energy. This raises the temperature of the atoms which t ...
Chapter 4 Galactic Chemical Evolution
... The material we find around us in the Universe today contains significant quantities of heavy elements, although these are still only minor contributors to the total mass of baryonic matter (most is hydrogen). These heavy elements have been synthesised in nuclear reactions in stars, a process known ...
... The material we find around us in the Universe today contains significant quantities of heavy elements, although these are still only minor contributors to the total mass of baryonic matter (most is hydrogen). These heavy elements have been synthesised in nuclear reactions in stars, a process known ...
Type II supernova
![](https://en.wikipedia.org/wiki/Special:FilePath/HST_SN_1987A_20th_anniversary.jpg?width=300)
A Type II supernova (plural: supernovae or supernovas) results from the rapid collapse and violent explosion of a massive star. A star must have at least 8 times, and no more than 40–50 times, the mass of the Sun (M☉) for this type of explosion. It is distinguished from other types of supernovae by the presence of hydrogen in its spectrum. Type II supernovae are mainly observed in the spiral arms of galaxies and in H II regions, but not in elliptical galaxies.Stars generate energy by the nuclear fusion of elements. Unlike the Sun, massive stars possess the mass needed to fuse elements that have an atomic mass greater than hydrogen and helium, albeit at increasingly higher temperatures and pressures, causing increasingly shorter stellar life spans. The degeneracy pressure of electrons and the energy generated by these fusion reactions are sufficient to counter the force of gravity and prevent the star from collapsing, maintaining stellar equilibrium. The star fuses increasingly higher mass elements, starting with hydrogen and then helium, progressing up through the periodic table until a core of iron and nickel is produced. Fusion of iron or nickel produces no net energy output, so no further fusion can take place, leaving the nickel-iron core inert. Due to the lack of energy output allowing outward pressure, equilibrium is broken.When the mass of the inert core exceeds the Chandrasekhar limit of about 1.4 M☉, electron degeneracy alone is no longer sufficient to counter gravity and maintain stellar equilibrium. A cataclysmic implosion takes place within seconds, in which the outer core reaches an inward velocity of up to 23% of the speed of light and the inner core reaches temperatures of up to 100 billion kelvin. Neutrons and neutrinos are formed via reversed beta-decay, releasing about 1046 joules (100 foes) in a ten-second burst. The collapse is halted by neutron degeneracy, causing the implosion to rebound and bounce outward. The energy of this expanding shock wave is sufficient to accelerate the surrounding stellar material to escape velocity, forming a supernova explosion, while the shock wave and extremely high temperature and pressure briefly allow for theproduction of elements heavier than iron. Depending on initial size of the star, the remnants of the core form a neutron star or a black hole. Because of the underlying mechanism, the resulting nova is also described as a core-collapse supernova.There exist several categories of Type II supernova explosions, which are categorized based on the resulting light curve—a graph of luminosity versus time—following the explosion. Type II-L supernovae show a steady (linear) decline of the light curve following the explosion, whereas Type II-P display a period of slower decline (a plateau) in their light curve followed by a normal decay. Type Ib and Ic supernovae are a type of core-collapse supernova for a massive star that has shed its outer envelope of hydrogen and (for Type Ic) helium. As a result, they appear to be lacking in these elements.