Denton ISD
... b. low in brightness but high in temperature c. average brightness and average in temperature d. average in brightness but high in temperature ...
... b. low in brightness but high in temperature c. average brightness and average in temperature d. average in brightness but high in temperature ...
3A8d
... of occasional instances of galaxies merging at the present time. In each case explain why the same observations are not as readily understood in the traditional formation/evolution model, which proposed that the formation of galaxies was largely completed in single rapid collapse events more than 10 ...
... of occasional instances of galaxies merging at the present time. In each case explain why the same observations are not as readily understood in the traditional formation/evolution model, which proposed that the formation of galaxies was largely completed in single rapid collapse events more than 10 ...
test - Scioly.org
... 40. Gas pressure and densities are much lower in giant stars than dwarfs. a. True b. False 41. When a star is in free-fall collapse, it is a protostar. a. True b. False 42. A star becomes a main sequence star when it is obtaining all its radiated energy from nuclear fusion of hydrogen to oxygen. a. ...
... 40. Gas pressure and densities are much lower in giant stars than dwarfs. a. True b. False 41. When a star is in free-fall collapse, it is a protostar. a. True b. False 42. A star becomes a main sequence star when it is obtaining all its radiated energy from nuclear fusion of hydrogen to oxygen. a. ...
Starry Lives, Starry Skies
... The handout sheet has examples of objects in each stage, but it would be good for students to use the Web or some astronomy books to find examples for themselves. 4. Have them make a star map of the location of one object for each stage, using the Your Sky Tonight star chart. Most sky objects a ...
... The handout sheet has examples of objects in each stage, but it would be good for students to use the Web or some astronomy books to find examples for themselves. 4. Have them make a star map of the location of one object for each stage, using the Your Sky Tonight star chart. Most sky objects a ...
Brightness vs. Distance
... The Atmospheric medium • Outside measuring the sun or the stars: Many possible conditions --clouds, fog, water vapor, air pollution, smoke. All absorb or scatter light which decreases the amount that comes through. • Also, sunlight and starlight reflect off the “top” of the atmosphere and never rea ...
... The Atmospheric medium • Outside measuring the sun or the stars: Many possible conditions --clouds, fog, water vapor, air pollution, smoke. All absorb or scatter light which decreases the amount that comes through. • Also, sunlight and starlight reflect off the “top” of the atmosphere and never rea ...
ASTR3007/4007/6007, Tutorial 4: Deuterium Burning in Protostars
... Exercise 5. Protostars typically have surface temperatures a bit cooler than the Sun. Assume our example 1 M star has a surface temperature T = 4000 K. What is its luminosity? Express your answer in Solar luminosities, L = 3.9 × 1033 erg s−1 . While the star is burning deuterium, it essentially ce ...
... Exercise 5. Protostars typically have surface temperatures a bit cooler than the Sun. Assume our example 1 M star has a surface temperature T = 4000 K. What is its luminosity? Express your answer in Solar luminosities, L = 3.9 × 1033 erg s−1 . While the star is burning deuterium, it essentially ce ...
Lecture10
... many hydrogen atoms have their electron in the n = 2 orbit: hence strong absorption ...
... many hydrogen atoms have their electron in the n = 2 orbit: hence strong absorption ...
Types of Stars http://space.about.com/od/stars/tp/What-Are
... Astronomers estimate that some red dwarf stars will burn for up to 10 trillion years. The smallest red dwarfs are 0.075 times the mass of the Sun, and they can have a mass of up to half of the Sun. 11. Supergiant Stars The largest stars in the Universe are supergiant stars. These are monsters with ...
... Astronomers estimate that some red dwarf stars will burn for up to 10 trillion years. The smallest red dwarfs are 0.075 times the mass of the Sun, and they can have a mass of up to half of the Sun. 11. Supergiant Stars The largest stars in the Universe are supergiant stars. These are monsters with ...
Star Fromation and ISM
... the core is dense and hot enough, fusion begins • The star still continues to collapse until the inward force of gravity is balanced by the outward pressure from the core. The star is now on the main sequence. • More massive stars follow the same ...
... the core is dense and hot enough, fusion begins • The star still continues to collapse until the inward force of gravity is balanced by the outward pressure from the core. The star is now on the main sequence. • More massive stars follow the same ...
Summary: Stellar Distances
... Interstellar dust makes stars look redder over long distances Temperatures can also be inferred from the appearance of a star’s spectrum - the pattern of spectral lines. This spectral typing is not affected by interstellar dust. Surface temperatures of stars almost all lie between 40,000°K for the “ ...
... Interstellar dust makes stars look redder over long distances Temperatures can also be inferred from the appearance of a star’s spectrum - the pattern of spectral lines. This spectral typing is not affected by interstellar dust. Surface temperatures of stars almost all lie between 40,000°K for the “ ...
Conservation of energy
... solar system can be determined by the analysis of some meteorites as well as of the solar spectrum It is representative of what is usually found in the Univers (cosmic abundances) within a common scale factor for carbon and heavier elements ...
... solar system can be determined by the analysis of some meteorites as well as of the solar spectrum It is representative of what is usually found in the Univers (cosmic abundances) within a common scale factor for carbon and heavier elements ...
Physics@Brock - Brock University
... Big Bang created hydrogen and some helium, along with a slew of other subatomic particles and electromagnetic radiation, but all the heavier elements were created inside stars. When the early massive stars “died” (their lifetimes were very short due to their enormous mass) the resulting explosions ( ...
... Big Bang created hydrogen and some helium, along with a slew of other subatomic particles and electromagnetic radiation, but all the heavier elements were created inside stars. When the early massive stars “died” (their lifetimes were very short due to their enormous mass) the resulting explosions ( ...
Giant Molecular Clouds and Gravitational Stability
... mass stars (~105), quiet slow star formation, mostly isolated star formation. • Ophiuchus (dist ≈ 140 pc, size ≈ 6 pc, mass ≈ 104 M): Low mass stars (~78), strongly clustered in western core (stellar density 50 stars/pc), high star formation efficiency • Orion (dist ≈ 400 pc, size ≈ 60 pc, mass ≈ 1 ...
... mass stars (~105), quiet slow star formation, mostly isolated star formation. • Ophiuchus (dist ≈ 140 pc, size ≈ 6 pc, mass ≈ 104 M): Low mass stars (~78), strongly clustered in western core (stellar density 50 stars/pc), high star formation efficiency • Orion (dist ≈ 400 pc, size ≈ 60 pc, mass ≈ 1 ...
Astronomy 1 – Winter 2011
... many hydrogen atoms have their electron in the n = 2 orbit: hence strong absorption ...
... many hydrogen atoms have their electron in the n = 2 orbit: hence strong absorption ...
General Introduction 1. Luminosity, Flux and Magnitude The
... can undergo supernova explosions in which the star is partially or totally disrupted, accompanied by a tremendous release of energy: in photonic emissions and kinetic energy, and, in some cases, neutrinos. Supernovae involving white dwarfs (products of low-mass stellar evolution) in binaries are the ...
... can undergo supernova explosions in which the star is partially or totally disrupted, accompanied by a tremendous release of energy: in photonic emissions and kinetic energy, and, in some cases, neutrinos. Supernovae involving white dwarfs (products of low-mass stellar evolution) in binaries are the ...
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.