absolute brightness: The apparent brightness a star would have if it
... Eddington limit: The limit beyond which the radiation force on matter is greater than the gravitational force. electric field: A field extending outward in all directions from a charged particle, such as a proton or an electron. The electric field determines the electric force exerted by the particl ...
... Eddington limit: The limit beyond which the radiation force on matter is greater than the gravitational force. electric field: A field extending outward in all directions from a charged particle, such as a proton or an electron. The electric field determines the electric force exerted by the particl ...
absolute brightness: The apparent brightness a star would have if it
... Eddington limit: The limit beyond which the radiation force on matter is greater than the gravitational force. electric field: A field extending outward in all directions from a charged particle, such as a proton or an electron. The electric field determines the electric force exerted by the particl ...
... Eddington limit: The limit beyond which the radiation force on matter is greater than the gravitational force. electric field: A field extending outward in all directions from a charged particle, such as a proton or an electron. The electric field determines the electric force exerted by the particl ...
Chapter 16 Star Birth Where do stars form? Star
... Collisions between particles in the cloud cause it to flatten into a disk ...
... Collisions between particles in the cloud cause it to flatten into a disk ...
Oscillating White Dwarf Stars Background on White Dwarfs
... Helium burning, often called the triple alpha process occurs above temperatures of 100.000.000 K. 8Be is unstable and decays back into He in 2.6 × 10–16 secs, but in the stellar interior a small equilibrium of 8Be exists. The 8Be ground state has almost exactly the energy of two alpha particles. In ...
... Helium burning, often called the triple alpha process occurs above temperatures of 100.000.000 K. 8Be is unstable and decays back into He in 2.6 × 10–16 secs, but in the stellar interior a small equilibrium of 8Be exists. The 8Be ground state has almost exactly the energy of two alpha particles. In ...
Black Holes, Part 3, Dark Energy
... which leaves the the protons at the core more able to repel each other. The process also creates an electron-dense shell around the plasma sphere, at its surface, where electric interaction occurs with external plasma streams, by which the plasma sun becomes a brilliant sphere emitting light. The en ...
... which leaves the the protons at the core more able to repel each other. The process also creates an electron-dense shell around the plasma sphere, at its surface, where electric interaction occurs with external plasma streams, by which the plasma sun becomes a brilliant sphere emitting light. The en ...
Modified True/False - Indicate whether the statement is true or false
... ____ 16. HS-ESS1-1 The process in which smaller atomic nuclei combine into larger atomic nuclei is known as a. Gravitational attraction. c. The Doppler effect. b. Parallax. d. Nuclear fusion. ____ 17. HS-ESS1-2 The apparent shift in a star’s position caused by the motion of the observer is called __ ...
... ____ 16. HS-ESS1-1 The process in which smaller atomic nuclei combine into larger atomic nuclei is known as a. Gravitational attraction. c. The Doppler effect. b. Parallax. d. Nuclear fusion. ____ 17. HS-ESS1-2 The apparent shift in a star’s position caused by the motion of the observer is called __ ...
File
... o Spiral galaxies have “arms” of stars that spiral outward from the center. The overall shape is round and flat like a plate, but the dense center of a spiral galaxy is spherical. Younger stars are more likely found in the arms of the spiral, and older stars are most likely found in the center sphe ...
... o Spiral galaxies have “arms” of stars that spiral outward from the center. The overall shape is round and flat like a plate, but the dense center of a spiral galaxy is spherical. Younger stars are more likely found in the arms of the spiral, and older stars are most likely found in the center sphe ...
9. Fascinating observations. But how much is well understood?
... The energy gained in this process is 7,275 MeV. The notation 8 Be * denotes a beryllium state with very short life time (2,6·10-16 s) and therefore the ignition of the 3-α-process needs high densities ( ρ > 10 6 g ⋅ cm −3 ) After the nuclear burst the accretion and burning of hydrogen continues so ...
... The energy gained in this process is 7,275 MeV. The notation 8 Be * denotes a beryllium state with very short life time (2,6·10-16 s) and therefore the ignition of the 3-α-process needs high densities ( ρ > 10 6 g ⋅ cm −3 ) After the nuclear burst the accretion and burning of hydrogen continues so ...
Notes on White Dwarfs and Neutron Stars.
... The larger the mass of the star, the smaller its radius! In fact, for the lower mass white dwarfs, we find R ∝ M −1/3 . This behavior can be derived from the virial theorem, making use of the P ∝ ρ5/3 equation of state, as you are asked to do in the homework. (The virial theorem approach will not, o ...
... The larger the mass of the star, the smaller its radius! In fact, for the lower mass white dwarfs, we find R ∝ M −1/3 . This behavior can be derived from the virial theorem, making use of the P ∝ ρ5/3 equation of state, as you are asked to do in the homework. (The virial theorem approach will not, o ...
Word doc - UC-HiPACC - University of California, Santa Cruz
... The moment photons began arriving at Earth shortly after midnight New Mexico time on Saturday, April 27, 2013, from the spectacular suicide of a massive star and resultant birth of a black hole, cameras began clicking on telescopes both on the ground and in space. Exultant astronomers worldwide capt ...
... The moment photons began arriving at Earth shortly after midnight New Mexico time on Saturday, April 27, 2013, from the spectacular suicide of a massive star and resultant birth of a black hole, cameras began clicking on telescopes both on the ground and in space. Exultant astronomers worldwide capt ...
Stars: Their Life and Afterlife
... be relatively dense (on the scale of the interstellar medium) and it needs to have a low pressure. Since pressure is related to temperature, this means the cloud needs to be cold, and typically it is clouds with temperatures that are initially ~ 10-50 K that host star formation. As a cloud of gas co ...
... be relatively dense (on the scale of the interstellar medium) and it needs to have a low pressure. Since pressure is related to temperature, this means the cloud needs to be cold, and typically it is clouds with temperatures that are initially ~ 10-50 K that host star formation. As a cloud of gas co ...
Nuclear Fusion - Orlando STC chapter
... Nuclear fusion occurs when the nuclei of two atoms combine to form the nucleus of a larger atom. Naturally, this can occur easily only with the smallest of elements, hydrogen, which has only one proton, and, in some cases, helium, which has two. Also, nuclear fusion can take place only when the at ...
... Nuclear fusion occurs when the nuclei of two atoms combine to form the nucleus of a larger atom. Naturally, this can occur easily only with the smallest of elements, hydrogen, which has only one proton, and, in some cases, helium, which has two. Also, nuclear fusion can take place only when the at ...
Astronomy Study Guide
... 44. Since astronomers can’t study a single star for billions of years, how do they know that stars go through stages in their lives? Astronomers study many stars and see how they differ from each other ...
... 44. Since astronomers can’t study a single star for billions of years, how do they know that stars go through stages in their lives? Astronomers study many stars and see how they differ from each other ...
Astrophysics - Mr Priest`s Physics Notes
... sky at different times of the year due to parallax with more distant stars. If the angle (called the parallax angle) p is equal to 1 arc-second the distance from the Earth to the star in question is 1 parsec. There are 360 degrees in a circle, 60 minutes in a degree and 60 seconds in an arc. ...
... sky at different times of the year due to parallax with more distant stars. If the angle (called the parallax angle) p is equal to 1 arc-second the distance from the Earth to the star in question is 1 parsec. There are 360 degrees in a circle, 60 minutes in a degree and 60 seconds in an arc. ...
Chapter 11: Stars
... temperature can only be inferred from models. • Surface T is easier to measure than its luminosity because it does not depend on distance. ...
... temperature can only be inferred from models. • Surface T is easier to measure than its luminosity because it does not depend on distance. ...
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.