Nuclear fusion in stars
... In the late 19th century Lord Kelvin and Hermann von Helmholtz proposed a mechanism to explain the source of the energy radiated by the Sun. They reasoned that as the Sun radiated energy, it would cool, lowering the gas pressure (which according to the ideal gas law is proportional to T ). This woul ...
... In the late 19th century Lord Kelvin and Hermann von Helmholtz proposed a mechanism to explain the source of the energy radiated by the Sun. They reasoned that as the Sun radiated energy, it would cool, lowering the gas pressure (which according to the ideal gas law is proportional to T ). This woul ...
December 1, 2011 - Perry Local Schools
... ones are closer to us and the dimmer ones are further away from us. We have just learned that stars vary a lot in the energy, and therefore the amount of light, they produce. ...
... ones are closer to us and the dimmer ones are further away from us. We have just learned that stars vary a lot in the energy, and therefore the amount of light, they produce. ...
Exam Name___________________________________
... 3) If you were to draw a straight line from the Sun to Mars and then watch this line as Mars moves along its orbit around the Sun, what would you see? A) The length of the line (measured in kilometers) would be the same in all parts of Mars's orbit. B) The area swept out by the line in 1 week would ...
... 3) If you were to draw a straight line from the Sun to Mars and then watch this line as Mars moves along its orbit around the Sun, what would you see? A) The length of the line (measured in kilometers) would be the same in all parts of Mars's orbit. B) The area swept out by the line in 1 week would ...
Exam 3 Solution Set - Indiana University Astronomy
... 0.5 solar masses is 1033 grams, which contains 1.5 x 1056 helium atoms. These are converted to 5 x 1055 carbon atoms. For each conversion, 0.013 x 10-24 grams are converted into energy. The total mass converted into energy is 5 x 1055 x 0.013 x 10-24 grams = 6.5 x 1029 grams. Since E=mc2, the energy ...
... 0.5 solar masses is 1033 grams, which contains 1.5 x 1056 helium atoms. These are converted to 5 x 1055 carbon atoms. For each conversion, 0.013 x 10-24 grams are converted into energy. The total mass converted into energy is 5 x 1055 x 0.013 x 10-24 grams = 6.5 x 1029 grams. Since E=mc2, the energy ...
solution
... pressure, density and temperature of the central region of a protostar. Once the temperature exceeds a few million K, H begins to fuse into He (via the p-p chain in a Sun-sized protostar, or the CNO cycle in a larger one). The energy released in the thermonuclear fusion reactions causes an outward p ...
... pressure, density and temperature of the central region of a protostar. Once the temperature exceeds a few million K, H begins to fuse into He (via the p-p chain in a Sun-sized protostar, or the CNO cycle in a larger one). The energy released in the thermonuclear fusion reactions causes an outward p ...
The Life Cycle of the Stars
... The birth of all stars is much like that of the Sun, but the mass of the gas and dust comprising the star will determine its precise destiny. Medium-sized stars like our Sun eventually use up their hydrogen fuel, cool and expand into red giants. Later they shed their outer layers and appear as a dif ...
... The birth of all stars is much like that of the Sun, but the mass of the gas and dust comprising the star will determine its precise destiny. Medium-sized stars like our Sun eventually use up their hydrogen fuel, cool and expand into red giants. Later they shed their outer layers and appear as a dif ...
Study Guide: Chapters 32-‐34 FROSH CHAPTER 32 1. What is
... 6. Name each body from our solar system described below. a. Oxygen rich atmosphere and running water ____________________________ b. Thick atmosphere causing the Greenhouse Effect ____________________________ c. ...
... 6. Name each body from our solar system described below. a. Oxygen rich atmosphere and running water ____________________________ b. Thick atmosphere causing the Greenhouse Effect ____________________________ c. ...
Can you write numbers in scientific notation
... Are you familiar with the composition of the Interstellar Medium (ISM)? Do you understand how the star formation process begins? How well you understand what processes are going on during the proto-star stage of a star’s life? What needs to happen for a proto-star to become a main sequence star? The ...
... Are you familiar with the composition of the Interstellar Medium (ISM)? Do you understand how the star formation process begins? How well you understand what processes are going on during the proto-star stage of a star’s life? What needs to happen for a proto-star to become a main sequence star? The ...
Astronomy 103 Final review session - Home | UW
... • End point for massive stars, leaving behind neutron star (pulsar) or black hole • Also end point for white dwarfs in binaries which grow in mass via accretion • Very energetic stellar explosion • Seeds elements into the interstellar medium • Can be used as a standard candle since luminosity known ...
... • End point for massive stars, leaving behind neutron star (pulsar) or black hole • Also end point for white dwarfs in binaries which grow in mass via accretion • Very energetic stellar explosion • Seeds elements into the interstellar medium • Can be used as a standard candle since luminosity known ...
Postgraduate Seminar Series Small Angle Neutron scattering on the anisotropic superconductor CaC6.
... vortex lattice is in the form of a ring, reflecting the absence of in-plane orientational order of the pyrolitic graphene planes. The temperature and field dependence of the scattered intensity allows the in-plane zero temperature value of the coherence length and the London penetration depth to be ...
... vortex lattice is in the form of a ring, reflecting the absence of in-plane orientational order of the pyrolitic graphene planes. The temperature and field dependence of the scattered intensity allows the in-plane zero temperature value of the coherence length and the London penetration depth to be ...
Analyzing Spectra
... 2. What are the five known substances in this activity? ________________________________________ Look closely at the spectrum below. Those black lines are caused by elements in the star's atmosphere. As light emitted from a star passes through the star's atmosphere, some of it is absorbed by element ...
... 2. What are the five known substances in this activity? ________________________________________ Look closely at the spectrum below. Those black lines are caused by elements in the star's atmosphere. As light emitted from a star passes through the star's atmosphere, some of it is absorbed by element ...
Geometry Questions
... 1. What is the acceleration due to gravity on the surface of a white dwarf? Let the mass of a white dwarf by approximately 1 solar mass, or 2.0 x 1030 kg, and its radius be approximately that of Earth or 6.4 x 106 m. (J63) 2. What is the acceleration due to gravity on the surface of a neutron star? ...
... 1. What is the acceleration due to gravity on the surface of a white dwarf? Let the mass of a white dwarf by approximately 1 solar mass, or 2.0 x 1030 kg, and its radius be approximately that of Earth or 6.4 x 106 m. (J63) 2. What is the acceleration due to gravity on the surface of a neutron star? ...
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... The effect is seen only when the smaller star eclipses the larger because the higher temperature exists on the inner faces. Since both the effect of ellipticity and the reflection effect result from the closeness of two stars it is difficult to separate one effect from the other. The proximity gives ...
... The effect is seen only when the smaller star eclipses the larger because the higher temperature exists on the inner faces. Since both the effect of ellipticity and the reflection effect result from the closeness of two stars it is difficult to separate one effect from the other. The proximity gives ...
PS #1 Solutions - Stars and Stellar Explosions 1. Opacity sources
... to Thompson scattering. We will carry out many related estimates during this course so it is important to become familiar with this process. Consider a star in hydrostatic equilibrium in which energy transport is by radiative diffusion. The star is composed of ionized hydrogen and is supported prima ...
... to Thompson scattering. We will carry out many related estimates during this course so it is important to become familiar with this process. Consider a star in hydrostatic equilibrium in which energy transport is by radiative diffusion. The star is composed of ionized hydrogen and is supported prima ...
Type II supernova
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.