Astronomy 242: Review Questions #1 Distributed: February 10
... 12. You observe a sample of Cepheid variable stars in a nearby galaxy. Plotting the average apparent K-band magnitude of each one against the period of pulsation yields Fig. 3. The straight line, a least-squares fit to the data, has the equation mK = 16.40 − 3.53 log(P/day). (a) Does it seem reasona ...
... 12. You observe a sample of Cepheid variable stars in a nearby galaxy. Plotting the average apparent K-band magnitude of each one against the period of pulsation yields Fig. 3. The straight line, a least-squares fit to the data, has the equation mK = 16.40 − 3.53 log(P/day). (a) Does it seem reasona ...
Multiple choice test questions 2, Winter Semester
... C) an object that emits random "pulses" of light, sometimes with only a fraction of a second between pulses and other times with several days between pulses D) a star that changes color rapidly, from blue to red and back again ...
... C) an object that emits random "pulses" of light, sometimes with only a fraction of a second between pulses and other times with several days between pulses D) a star that changes color rapidly, from blue to red and back again ...
Learning Objectives Weeks 9-11 . 1. Know that star birth can begin
... 10. The burned-out core of a moderately low-mass star cools and contracts until it becomes a white dwarf. A white dwarf is kept from collapsing by the pressure of its degenerate electrons. 11. High-mass stars create heavy elements in their cores. A star of 8 or more solar masses evolves into a super ...
... 10. The burned-out core of a moderately low-mass star cools and contracts until it becomes a white dwarf. A white dwarf is kept from collapsing by the pressure of its degenerate electrons. 11. High-mass stars create heavy elements in their cores. A star of 8 or more solar masses evolves into a super ...
Star and Sun Properties
... • The Sun, our closest star, is 93 million miles from Earth. • The next closest star is 4.3 lighter years away. • By mass, the Sun is 71 % Hydrogen, 27% helium and the rest heavier element. This is similar to the composition of the universe. • The Sun is about 4.6 billion years old. ...
... • The Sun, our closest star, is 93 million miles from Earth. • The next closest star is 4.3 lighter years away. • By mass, the Sun is 71 % Hydrogen, 27% helium and the rest heavier element. This is similar to the composition of the universe. • The Sun is about 4.6 billion years old. ...
Chapter 1 Vocabulary – The Puzzled of Matter
... Nebula – a large cloud of gas and dust spread out over a large volume of space Protostar – a contracting nebula with enough mass to form a star Planetary Nebula – a glowing cloud of gas surrounding a dying low-mass star Supernova – an enormous explosion in which the byproducts of a supergiant star’s ...
... Nebula – a large cloud of gas and dust spread out over a large volume of space Protostar – a contracting nebula with enough mass to form a star Planetary Nebula – a glowing cloud of gas surrounding a dying low-mass star Supernova – an enormous explosion in which the byproducts of a supergiant star’s ...
Loving The Universe
... Substance Of Life Life requires H, C, O, & N All elements of life came from stars that lived AND DIED before the sun formed. Sun is a 2nd or 3rd generation star o 1st stars were pure hydrogen and helium) ...
... Substance Of Life Life requires H, C, O, & N All elements of life came from stars that lived AND DIED before the sun formed. Sun is a 2nd or 3rd generation star o 1st stars were pure hydrogen and helium) ...
Nuclear Reactions
... If the Sun was all hydrogen which was all converted to helium the energy released would be 0.007xMSunc2 = 1.26 x 1045 joules The Sun could then shine at its present luminosity for 110 x 109 years But the Sun isn’t all hydrogen and not all of the Sun’s hydrogen can be fused to make helium.......... ...
... If the Sun was all hydrogen which was all converted to helium the energy released would be 0.007xMSunc2 = 1.26 x 1045 joules The Sun could then shine at its present luminosity for 110 x 109 years But the Sun isn’t all hydrogen and not all of the Sun’s hydrogen can be fused to make helium.......... ...
Measuring Distances Beyond the Solar System The Characteristics
... Light travelling from the Sun distance 0.000016 ly away, takes approximately 8 minutes to reach Earth Light travelling from Vega distance 25 ly takes approximately 25 years to reach Earth. ...
... Light travelling from the Sun distance 0.000016 ly away, takes approximately 8 minutes to reach Earth Light travelling from Vega distance 25 ly takes approximately 25 years to reach Earth. ...
S03 from fusion to all the elements.notebook
... fuse to form __________. In the next step, another hydrogen atom fuses with the deuterium, creating a rare isotope of helium that has two protons and one neutron in its nucleus. In the third step, two of the rare helium atoms fuse to create a single normal helium atom and two hydrogen atoms. The f ...
... fuse to form __________. In the next step, another hydrogen atom fuses with the deuterium, creating a rare isotope of helium that has two protons and one neutron in its nucleus. In the third step, two of the rare helium atoms fuse to create a single normal helium atom and two hydrogen atoms. The f ...
The Sun*s
... Eventually the helium is exhausted, and the star collapses again. If it is massive enough, then the temperature increases enough to allow carbon fusion. The cycle repeats, fusing heavier elements each time, until the core temperature cannot rise any higher. At this point, the star “dies”. ...
... Eventually the helium is exhausted, and the star collapses again. If it is massive enough, then the temperature increases enough to allow carbon fusion. The cycle repeats, fusing heavier elements each time, until the core temperature cannot rise any higher. At this point, the star “dies”. ...
Lab 1-2 : Vocabulary
... Big Bang- theory that all matter and energy in the universe was compressed into an extremely small volume that suddenly began expanding in all directions billions of ...
... Big Bang- theory that all matter and energy in the universe was compressed into an extremely small volume that suddenly began expanding in all directions billions of ...
Summary for week #2
... for the billions of years implied by the ages of rocks and meteorites, though gravitational contraction is an important process that explains how gas collapsing to form stars gets hot in the first place. Einstein’s special theory of relativity revealed that mass was a form of energy, with the conver ...
... for the billions of years implied by the ages of rocks and meteorites, though gravitational contraction is an important process that explains how gas collapsing to form stars gets hot in the first place. Einstein’s special theory of relativity revealed that mass was a form of energy, with the conver ...
powerpoint version
... Now have a mass-luminosity diagram for Main Sequence stars. This tells us that the heavier they are, the greater is their energy output rate i.e. Luminosity (mass mass mass mass) but Total energy available mass Therefore, low mass stars live longer. ...
... Now have a mass-luminosity diagram for Main Sequence stars. This tells us that the heavier they are, the greater is their energy output rate i.e. Luminosity (mass mass mass mass) but Total energy available mass Therefore, low mass stars live longer. ...
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.