Neutron Stars PowerPoint
... – Thought to have solid crust of ordinary neutrons – Thought to have fluid interior of degenerate neutrons ...
... – Thought to have solid crust of ordinary neutrons – Thought to have fluid interior of degenerate neutrons ...
Accretion
... R~10,000km so nuclear burning more efficient by factor of ~50 • Accretion still an important process however: - nuclear burning on surface => nova outburst - accretion important for much of lifetime ...
... R~10,000km so nuclear burning more efficient by factor of ~50 • Accretion still an important process however: - nuclear burning on surface => nova outburst - accretion important for much of lifetime ...
Luminosity - U of L Class Index
... • What is the significance of the main sequence? Normal stars that fuse H to He in their cores fall on the main sequence of an H-R diagram A star’s mass determines its position along the main sequence (high-mass: luminous and blue; low-mass: faint and red) ...
... • What is the significance of the main sequence? Normal stars that fuse H to He in their cores fall on the main sequence of an H-R diagram A star’s mass determines its position along the main sequence (high-mass: luminous and blue; low-mass: faint and red) ...
Stellar Physics - Craigie High School
... A dense star with a sufficiently large mass/small radius could have an escape velocity greater than 3 x 108 m s-1. This means that light emitted from its surface could not escape - hence the name black hole. The physics of the black hole cannot be explained using Newton’s Theory. The correct theory ...
... A dense star with a sufficiently large mass/small radius could have an escape velocity greater than 3 x 108 m s-1. This means that light emitted from its surface could not escape - hence the name black hole. The physics of the black hole cannot be explained using Newton’s Theory. The correct theory ...
Lecture 28 Formation of chemical elements
... Those due to the r- and s- processes include: Abundances of >Z=56 elements are low are vary much less with Z No stable isotopes above z=83 (Bi), but long-lived radioactive Th and U, + their transient radioactive daughter isotopes, still exist in our solar system today. Other radioactive transuranics ...
... Those due to the r- and s- processes include: Abundances of >Z=56 elements are low are vary much less with Z No stable isotopes above z=83 (Bi), but long-lived radioactive Th and U, + their transient radioactive daughter isotopes, still exist in our solar system today. Other radioactive transuranics ...
EarthComm_c1s9
... Scientists also search for examples of planetary nebulae. They want to understand when and how these events occur. Not only are these nebulae interesting, but they also show scientists what the fate of our solar system will be billions of years from now. What would happen if there were a supernova e ...
... Scientists also search for examples of planetary nebulae. They want to understand when and how these events occur. Not only are these nebulae interesting, but they also show scientists what the fate of our solar system will be billions of years from now. What would happen if there were a supernova e ...
5.1 Introduction and Definitions
... gas overlying the opaque interior. The photons produced there carry away the gravitational energy released when the star forms from a collapsing gas cloud, the energy released by the thermonuclear reactions taking place in the core of the star during its lifetime and, once thermonuclear reactions st ...
... gas overlying the opaque interior. The photons produced there carry away the gravitational energy released when the star forms from a collapsing gas cloud, the energy released by the thermonuclear reactions taking place in the core of the star during its lifetime and, once thermonuclear reactions st ...
Chapter 29 Notes-
... • In Einstein’s equation E = mc2, E represents energy produced; m represents the mass; and c represents the speed of light, which is about 300,000 km/s. • Einstein’s equation can be used to calculate the amount of energy produced from a given amount of matter. • By using Einstein’s equation, astrono ...
... • In Einstein’s equation E = mc2, E represents energy produced; m represents the mass; and c represents the speed of light, which is about 300,000 km/s. • Einstein’s equation can be used to calculate the amount of energy produced from a given amount of matter. • By using Einstein’s equation, astrono ...
29.1 Directed Reading Guide
... _____ 55. What is the size of the sun’s core? a. 25% of 1,390 km b. 25% of 13,900 km c. 25% of 139,000 km d. 25% of 1,390,000 km 56. What is the sun’s core made up of? _______________________________________________________________ 57. How does the mass of the sun compare with the mass of Earth? ___ ...
... _____ 55. What is the size of the sun’s core? a. 25% of 1,390 km b. 25% of 13,900 km c. 25% of 139,000 km d. 25% of 1,390,000 km 56. What is the sun’s core made up of? _______________________________________________________________ 57. How does the mass of the sun compare with the mass of Earth? ___ ...
Fusion
... The pressure in the center of the sun equals the weight per unit area of the material on top. We can approximate central pressure: ...
... The pressure in the center of the sun equals the weight per unit area of the material on top. We can approximate central pressure: ...
Problems_blackbody_spectra_hr
... Above are three spectral curves showing stars A, X, Y, Z. Star A is shown in all of the plots as a point of comparison. Assume that stars A and Y are the same size. 7. Between stars A and Y, which star looks redder? Explain your reasoning. ...
... Above are three spectral curves showing stars A, X, Y, Z. Star A is shown in all of the plots as a point of comparison. Assume that stars A and Y are the same size. 7. Between stars A and Y, which star looks redder? Explain your reasoning. ...
chap11 (WP)
... Sun's core, it is high enough to initiate nuclear reactions. Since the gravitational binding energy scales as a function of a star's mass like M2, then the binding energy per particle scales like M (ignoring the slow increase in the star's radius with mass). So, a star several times the Sun's mass c ...
... Sun's core, it is high enough to initiate nuclear reactions. Since the gravitational binding energy scales as a function of a star's mass like M2, then the binding energy per particle scales like M (ignoring the slow increase in the star's radius with mass). So, a star several times the Sun's mass c ...
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.